MCAT chem ch 1 Atomic structure and periodic structure

Aufbau principle

electrons fill lower energy orbitals first to create the most stable electronic configuration, fill orbitals in order of inc energy level, from lower to higher energy levels Order; 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d

Question 17 True or false: The highest energy electrons can be found closest to the nucleus. True False

Explanation This statement is false. Electrons in orbitals closest to the nucleus are the lowest in energy and the most stable. In contrast, the farther away an orbital is from the nucleus, the less its electrons experience the attractive forces from nuclear protons, and thus the more energy and less stability they have.

List the following ions in descending order from the smallest number of electrons to the largest number of electrons. Drag and drop selections into the correct order. Sulfite (SO32-) Nitrate (NO3-) Hypochlorite (ClO-) Ferrous ion (Fe2+)

The correct answer is ferrous ion (Fe2+), hypochlorite (ClO-), nitrate (NO3-), and then sulfite (SO32-). Ferrous iron carries a +2 charge, so it has 24 electrons. Hypochlorite carries a -1 charge, so it has 26 electrons. Nitrate carries a -1 charge, so it has 32 electrons. Sulfite carries a -2 charge, so it has 42 electrons.

Electronic config of Hg

[Xe] 4f14 5d10 6s2

Atomic effect or radius

decreases across a period, more protons and elec are added, number of protons and elec increases, poor shielding of valence elec increases down a group, n increases and shielding effects increase, large radius = bottom left more shiedling effect

Trends to remember

atomic/ionic radius, EN, electron affinity, ionization energy nature of atom's behavior nuclear charge = Z actual attractive force of positively charged nucleus on atom's valence electrons = Zeff (effective nuc charge) shielding effect: inner electrons shield outer elec from nucleus, electrostatic attraction between nuc and outer elec decreases, shielding effect is lower across the row, valence elec shield each other poorly

Valence electrons

Electrons closer to nucleus, more stability and lower potential energy, energy and stability are inverse electrons are said to relax or decay if it is in an excited tate and moves to a lower eergy level, photons are subatomic particles that make up light emitted photons have exactly same energy required for promotion of electron emitted and basorbed in the form of electromagnetic radiation (both fields), electromag spectrum includes EM radiatio visible light radio gamma and X rays microwaves, different forms of EM radiation differ in enenrgy freq, WV, energy of EM radiation = hf (h=6.63* 10 ^-34 J/s), f= freq of light, freq of wave = c (speed of light)/wavelength

Match the names of each compound with its chemical formula. Drag and drop selections into the empty slot under the corresponding answer. FeCl2 ClO3- SO32- ClO2- NO2- SO42- FeCl3 NO3- Ferrous chloride Chlorite Sulfate Nitrite Sulfite Chlorate Nitrate Ferric chloride

Explanation To distinguish between ferrous chloride and ferric chloride, it is necessary to infer the charge present on the Fe atom in those compounds, keeping in mind that chlorine forms an anion with a 1- charge. Therefore, in FeCl2, Fe must have a 2+ charge, making it ferrous chloride. Correspondingly, in FeCl3, Fe must have a 3+ charge, making it ferric chloride.The remaining examples given in this question are anions that contain oxygen. For oxyanions, -ite is used as the suffix for anions with fewer oxygen atoms and -ate for anions with more oxygen atoms.

Question 6 What happens when an electron jumps from shell n = 2 to shell n = 1? Select all that apply. A The electron becomes excited. B A photon is emitted. C Energy is absorbed by the electron. D The electron moves to a more stable state.

The electron becomes excited. Incorrect Answer The electron is moving from a higher energy shell to a lower energy shell, so it is moving to a more stable state. A photon is emitted. Correct Answer A photon is emitted when an electron jumps from a higher energy shell to a lower energy shell. C Energy is absorbed by the electron. Incorrect Answer If energy is absorbed by the electron, it becomes excited and jump from a lower energy shell to a higher energy shell. The electron moves to a more stable state. Correct Answer When an electron jumps from a higher shell to a lower shell, it is moving to a lower energy, more stable state.

Hund's rule

each orbital holds upto two paired electrons with opposite spin, like charges repel so electrons will occupy orbitalswith the lowest energy configuration first. will align with magnetic field, occupying orbitals in a spin up config before forced to spin pair with one aligned against the magnetic field all orbitals must be at least half filled in the spin up config, no two paired electrons in the same orbital until all orbitals are half filled first

Question 2 Which of the following sets of quantum numbers cannot represent the locations of two electrons in an atom? Select all that apply. A 1, 0, 0, +1/2 and 1, 0, 0, +1/2 B 1, 0, 2, -1/2 and 1, 0, 2, +1/2 C 3, 1, 0, +1/2 and 3, 2, 1, +1/2 D 1, 0, 0, +1/2 and 3, 1, 0, -1/2

1, 0, 0, +1/2 and 1, 0, 0, +1/2 Correct Answer The question stem asks us to identify a set of quantum numbers that cannot represent the location of two electrons in an atom. This answer choice specifies the exact same quantum number for both electrons. According to the Pauli exclusion principle, no two electrons in a given atom can have the exact same four quantum numbers because they can't occupy the exact same space at the exact same time. B 1, 0, 2, -1/2 and 1, 0, 2, +1/2 Correct Answer While these numbers would satisfy the Pauli exclusion principle, it is not possible to have a magnetic quantum number (the third number) that is larger than the azimuthal quantum number (the second number). Therefore, this set of quantum numbers does not describe a possible location for electrons in an atom. C 3, 1, 0, +1/2 and 3, 2, 1, +1/2 Incorrect Answer The quantum numbers satisfy the Pauli exclusion principle because they are different, and they accurately represent a possible location in the atom. Therefore, this set of quantum numbers could technically represent the location of two electrons in an atom. 1, 0, 0, +1/2 and 3, 1, 0, -1/2 Incorrect Answer The quantum numbers satisfy the Pauli exclusion principle because they are different, and they accurately represent a possible location in the atom. Therefore, this set of quantum numbers could technically represent the location of two electrons in an atom.

How many protons, neutrons, and electrons are in 39Ca2+? A 19 protons, 19 neutrons, 17 electrons Incorrect Answer This results from miscalculation. B 19 protons, 20 neutrons, 18 electrons Incorrect Answer This results from miscalculation. C 20 protons, 21 neutrons, 17 electrons Incorrect Answer This results from miscalculation. 20 protons, 19 neutrons, 18 electrons

39Ca2+ is a charged isotope of calcium. Its mass number is 39, and it contains 20 protons by definition; therefore, it has 19 neutrons. The number of electrons listed is correct. Neutral calcium has 20 electrons because there are 20 protons. Therefore, Ca2+ will have two fewer electrons than protons.

Question 12 Which of the following orbitals cannot exist in an s subshell? Select all that apply. A 0 B -1 C +1 D +2

A 0 Incorrect Answer The question stem asks for orbitals that cannot exist. The magnetic quantum number, ml, ranges from -l to +l for a given subshell. The s subshell (l = 0) has just 1 orbital, so ml = 0. Thus, there is only one possible orientation in space for this subshell. -1 Correct Answer The magnetic quantum number, ml, ranges from -l to +l for a given subshell. The s subshell (l = 0) has just 1 orbital, so ml = 0. Thus, there is only one possible orientation in space for this subshell. C +1 Correct Answer The magnetic quantum number, ml, ranges from -l to +l for a given subshell. The s subshell (l = 0) has just 1 orbital, so ml = 0. Thus, there is only one possible orientation in space for this subshell. D +2 Correct Answer The magnetic quantum number, ml, ranges from -l to +l for a given subshell. The s subshell (l = 0) has just 1 orbital, so ml = 0. Thus, there is only one possible orientation in space for this subshell. Next

What is the charge on a phosphate ion with 39 protons and 41 electrons? A 2+ B 2- C Neutral D Cannot be determined without knowing the total number of neutrons.

A 2+ Incorrect Answer There are more electrons than protons, so this ion should be negatively charged, not positively charged. 2- Correct Answer There are 2 more electrons than protons, so this polyatomic ion will carry a 2- charge. C Neutral Incorrect Answer Neutral molecules need to have an equal number of protons and electrons so that the opposite charges will cancel out. There are 2 more electrons than protons, so this ion should have a 2- charge. D Cannot be determined without knowing the total number of neutrons. Incorrect Answer The number of neutrons will not affect the charge of the ion because neutrons do not have a charge. Therefore, the charge of the ion can be calculated without knowing how many neutrons are present.

Question 11 How many electrons can the n = 2 shell hold? A 4 B 8 C 16 D 32

A 4 Incorrect Answer This results from miscalculation. 8 Correct Answer The n = 2 shell is made up of the s subshell and p subshell. The s subshell has one orbital that can hold 2 electrons. The p subshell has 3 orbitals (-1, 0, +1) that can each hold two electrons for a total of 6 electrons. This means there are a total of 8 electrons in the n = 2 shell. C 16 Incorrect Answer This results from miscalculation. D 32 Incorrect Answer This results from miscalculation.

Question 3 Which of the following values will change by the greatest amount when an oxygen atom loses a single neutron? A Atomic number B Mass number C Atomic weight D Molecular weight

A Atomic number Incorrect Answer The atomic number is defined by the number of protons in an atom. Since only the number of neutrons has changed, the atomic number will remain the same. Mass number Correct Answer The mass number is the sum of protons and neutrons in an atom. Because oxygen has lost a neutron, the mass number will decrease by 1. C Atomic weight Incorrect Answer Atomic weight is a term that tells us the weighted average mass of an atom of a certain element, accounting for all possible isotopes of that element. One single atom losing a neutron will not significantly affect this average, so the atomic weight of oxygen will not change. D Molecular weight Incorrect Answer Molecular weight only applies to molecules which are made up of two or more atoms bonded together. We are only dealing with a single oxygen atom, so molecular weight is not relevant.

Question 2 Which of the following best describes a nitrogen atom after it has lost a proton? A Nitrogen becomes an isotope with a mass number that has decreased by 1 amu. B The molecular weight of nitrogen decreases by 1 amu. C Nitrogen becomes carbon-12. D Nitrogen becomes carbon-13.

A Nitrogen becomes an isotope with a mass number that has decreased by 1 amu. Incorrect Answer When an atom loses a neutron, it becomes an isotope of that same element. When an atom loses a proton, it becomes an entirely new element. The molecular weight of nitrogen decreases by 1 amu. Incorrect Answer Molecular weight is the weight of an entire molecule, and by definition, molecules are made up of two or more atoms. Because we are only talking about a single nitrogen atom, molecular weight does not apply here. C Nitrogen becomes carbon-12. Incorrect Answer When nitrogen loses one proton, it will become an isotope of carbon, but that carbon will still have 7 neutrons, which is the same number of neutrons in nitrogen. Seven neutrons plus six protons is equal to a mass number of 13, making this atom carbon-13. D Nitrogen becomes carbon-13. Correct Answer When nitrogen loses one proton, it will become an isotope of carbon, but that carbon will still have 7 neutrons, which is the same number of neutrons in nitrogen. Seven neutrons plus six protons is equal to a mass number of 13, making this atom carbon-13.

Question 10 Consider two atoms in the gas phase. Compared to Ne, one would expect O2− to have: A. a larger radius. B. a greater atomic mass. C. a different electron configuration. D. the same nuclear charge.

A is correct. Although they have the same number of electrons in the same configuration, O2− has a smaller nuclear charge (number of protons) than Ne. This causes its electrons to be more loosely attracted to the nucleus, which gives it a larger atomic radius than Ne. Choice B is incorrect because O2− has a smaller atomic mass than Ne. larger ionic radius (same number of protons as neutral O), extra elec added give it a larger radius

Question 12 What is the electron configuration of mercury? A. [Xe] 4f14 5d10 6s2 B. [Xe] 4f8 5d10 6s2 6p6 C. [Rn] 4f8 5d10 6s2 6p6 D. [Xe] 5f14 5d10 6s2

A is correct. Elemental mercury has full 4f, 5d and 6s subshells. To arrive at this answer, use the Aufbau principle. In the case of metals, drawing the diagram from Figure 6 can be very helpful in filling orbitals correctly from lowest to highest energy level. In this case, they should be filled up in order: 6s → 4f → 5d. Answer choice B makes a tempting mistake by filling the more energetic 6p subshell first. Answer choice C does this as well but incorrectly makes use of abbreviated notation. Answer choice D fails to account for the fact that the f subshell occurs at n-2. Since we are on the 6th energy level, the corresponding f subshell must be 4.

Question 3 Light at a wavelength of 254 nm damages microbes. Given this information, as well as the information contained in the passage, which of the following strategies would be most suitable for constructing a germicidal lamp capable of disinfecting surfaces? A. Using a mercury vapor lamp, but removing the phosphor B. Incorporating mercury into the phosphor C. Increasing the energy of the 254-nm light emitted by the mercury gas D. Increasing the amount of mercury in the lamp, while retaining the phosphor

A is correct. Given the information in the question, to construct a germicidal lamp, we need to find a way to deliver the 254-nm light emitted by the mercury to microbes on a surface. Since the phosphor essentially acts to convert the 254-nm ultraviolet light emitted by mercury into light waves in the visible range, removing the phosphor would eliminate this step and allow the 254-nm light to reach the surface. B: If mercury was incorporated into the phosphor, some would presumably be ionized, but it would be more efficient to just remove the phosphor entirely. Additionally, the passage indicates that phosphors are composed of somewhat complex molecules with non-obvious behaviors, so we cannot rule out the possibility that mercury might interact with the phosphor in a way that could interfere with its emission behavior. C: Since the energy of a photon is defined by its frequency/wavelength, its energy cannot be increased. D: Increasing the amount of mercury without removing the phosphor would not accomplish the goal described in the question stem.

Question 14 Within a hemoglobin subunit, diatomic oxygen binds a coordinated Fe2+ ion, temporarily oxidizing it to Fe3+ . In this case, oxygen acts as: A. an electron acceptor, because it is more electronegative than Fe2+. B. an electron acceptor, because it is less electronegative than Fe2+. C. an electron donor, because it is more electronegative than Fe2+. D. an electron donor, because it is less electronegative than Fe2+.

A is correct. The increased oxidation state of the iron ion reflects a loss of electron density, which must have been accepted by the oxygen molecule. The tendency of an atom to attract electron density towards itself is associated with electronegativity. EN= electron acceptor, increased electron density, electron density/attraction towards itself https://forums.studentdoctor.net/threads/stabilization-and-electron-withdrawing-groups.689310/ https://forums.studentdoctor.net/threads/electron-withdrawing-donating-groups.411177/

According to the periodic table, how many valence electrons does carbon have?

According to the electron configuration expected for carbon from its position in the periodic table, carbon will have two electrons in the 1s subshell, two electrons in the 2s subshell and two electrons in the 2p orbital. For elements with p subshells, the electrons in their s and p subshell with the highest principal quantum number are valence electrons. This means we should only count electrons from the 2s and 2p subshell as valence electrons for carbon. Two electrons from the 2s subshell and two electrons from the 2p subshell make for a total of 4 valence electrons. Another way to determine this quickly is to see that carbon is 4 blocks away from the left element on the periodic table. Thus, it has 4 valence electrons.

Which of the following statements could be true according to the Heisenberg uncertainty principle? Select all that apply. A An electron is located at coordinates x, y, z travelling at 800 m/s. B An electron is located at coordinates x, y, z travelling at an unknown velocity. C An electron is travelling at 800 m/s from an unknown location. D An electron is most likely located in the d orbital as it travels at 800 m/s.

B An electron is located at coordinates x, y, z travelling at an unknown velocity. Correct Answer According to the Heisenberg uncertainty principle, it is impossible to precisely know both the exact location and the exact momentum of an electron at any given moment in time. In this case, we know the precise location of the electron represented by coordinates x, y and z, but we know very little about its velocity. C An electron is travelling at 800 m/s from an unknown location. Correct Answer According to the Heisenberg uncertainty principle, it is impossible to precisely know both the exact location and the exact momentum of an electron at any given moment in time. In this case, we know the precise velocity of the electron, but we know very little about its precise location. An electron is most likely located in the d orbital as it travels at 800 m/s. Correct Answer According to the Heisenberg uncertainty principle, it is impossible to precisely know both the exact location and the exact momentum of an electron at any given moment in time. In this case, we know the precise velocity of the electron, but we cannot know its precise location. All we know is roughly which orbital the electron is in.

Question 1 What is the correct electron configuration of Mn2+? A. 1s22s22p63s23p63d54s2 B. 1s22s22p63s23p63d5 C. 1s22s22p63s23p63d34s2 D. 1s22s22p63s23p63d74s2

B is correct. Following Aufbau rules, the electron configuration of Mn is 1s22s22p63s23p63d54s2 (choice A). Two electrons need to be lost to create Mn2+, and those electrons are taken from the 4s orbital, yielding 1s22s22p63s23p63d5. A: This is the electron configuration of Mn, not Mn2+. C: This answer choice erroneously takes electrons from the 3d orbital. D: This answer choice incorrectly adds electrons, instead of removing them, to form a positive ion.

Question 15 Which of the following atoms is expected to have the greatest first ionization energy? A. Calcium B. Bromine C. Sodium D. Copper

B is correct. Ionization energy refers to the energy that must be expended to completely remove an electron from an atom. In general, ionization energy increases from left to right along the periodic table. Bromine is a halogen and belongs to Group 17 in the periodic table, while calcium, sodium, and copper are metals; thus, bromine is the farthest to the right and is expected to have the highest first ionization energy. Alternatively, one might consider that bromine could achieve a full octet configuration if it were to gain just one electron. Therefore, the loss of an electron would be unfavorable.

Question 7 In its elemental form, which component of Ca5(PO4)3Cl has three unpaired p electrons? A. Ca B. P C. O D. Cl

B is correct. The most systematic way to approach this question is to work through the electron configurations of these elements, as follows: calcium = [Ar]4s2, phosphorus = [Ne]3s23p3, oxygen = [He]2s22p4, and chlorine = [Ne]3s23p5. Calcium can be immediately eliminated, since its 3p orbital is completely full. The remaining three elements have 3, 4, and 5 p electrons, respectively, distributed among 3 p orbitals. Therefore, phosphorus, with 3 p electrons, is the element with 3 unpaired p electrons. A: In Ca, the 3p orbital is completely full, and it has no 4p electrons. C, D: O and C have 4 and 5 p electrons, meaning that they will have 2 and 1 unpaired electrons, respectively.

Question 9 Which of the following, together with a neutral carbon atom, would comprise an isoelectronic pair? A. O2− B. C+ C. B− D. N−

C is correct. An uncharged carbon atom has six electrons in the configuration 1s22s22p2. Neutral boron has the configuration 1s22s22p1. The addition of one electron to a neutral boron atom will confer upon it the same electronic configuration as neutral carbon, making the pair isoelectronic. This is not true of any of the other options.

Question 5 Researchers are interested in investigating how the electron distribution in calcium halophosphate phosphor affects its light emission properties. Which variation of the phosphor would have the most even electron distribution? A. Ca5(PO4)3F B. Ca5(PO4)3Cl C. Ca5(PO4)3Br D. Ca5(PO4)3OH 22.31% A 7.91% B 40.14% C

C is correct. Since these compounds only differ in terms of the halogen (or hydroxyl group) at the end, and electronegativity means that an atom pulls electrons towards itself, the compound with the least electronegative halogen or hydroxyl substituent at the end will have the most even electron distribution. Electronegativity increases from left to right across the periodic table, peaking with the halogens, but then decreases as we move down. Of the halogen substituents, Br is the least electronegative. Oxygen, which is found in OH, is near F at the top of the periodic table, and is the second most electronegative element. Therefore, Br is the least electronegative substituent of the options presented in this question, and Ca5(PO4)3Br will have the most even electron distribution. A, B, D: The elements F, Cl, and O are more electronegative than Br, which would result in a less even electron distribution.

Question 4 What is the energy of the photon emitted by mercury in a fluorescent lamp? A. 7.8 × 10-18 J B. 1.7 × 10-31 J C. 7.8 × 10-19 J D. 5.1 × 10-32 J

C is correct. Since we are given the wavelength of the photon (254 nm), the most efficient way to tackle this problem is to use the equation E = hc/ λ, where h = 6.63 × 10−34 m2kg/s and c = 3.0 × 108 m/s. In scientific notation, 254 nm = 2.54 × 10−7 m. Dropping units to simplify our calculations, and rounding as we go, we get E = (6.63 × 10−34)( 3.0 × 108 m/s)/( 2.54 × 10−7 m) = (2 × 10−25)/(2.54 × 10−7) = (0.8 × 10−18) = 8 × 10−19. This is very close to the correct answer, 7.8 × 10−19 J. A, B, D: These answers result from miscalculation.

Question 8 Which quantum number describes the spatial orientation of a specific orbital within a given electronic subshell? A. Principal quantum number B. Spin quantum number C. Magnetic quantum number D. Angular momentum quantum number

C is correct. The magnetic quantum number distinguishes between different orbitals in a given subshell and describes their orientation in space. Since this question asks about the orientation of an orbital within a subshell, the best answer here is choice C.

Question 2 What happens when fluorine loses a neutron? A It becomes an anion. B It becomes a cation. C It forms a new isotope. D It becomes a new element.

Changing the number of neutrons of an atom will change its isotopic identity. Some isotopes are significantly more abundant in nature than others, but many elements do have multiple stable isotopes. Keep in mind that all configurations of an atom are isotopes, whether they are the most common isotope or not. Incorrect Answer The elemental identity of an atom changes when it loses or gains a proton. Anions are formed when atoms gain electrons. B It becomes a cation. Incorrect Answer Cations are formed when atoms lose electrons.

Question 7 What is the molecular formula of perchlorate? A ClO- B ClO2- C ClO3- D ClO4-

ClO- Incorrect Answer Anions that contain oxygen, called oxyanions, use -ite as the suffix for anions with fewer oxygen atoms and -ate for anions with more oxygen atoms as in nitrite versus nitrate or chlorite and chlorate. Perchlorate ends in -ate, so an answer choice with more oxygens is probably correct. B ClO2- Incorrect Answer Anions that contain oxygen, called oxyanions, use -ite as the suffix for anions with fewer oxygen atoms and -ate for anions with more oxygen atoms as in nitrite versus nitrate or chlorite and chlorate. The anion with one fewer oxygen atoms than the -ite anion uses the prefix hypo- as in hypochlorite, and the anion with one more oxygen atom than the -ate anion uses the prefix per- as in perchlorate. C ClO3- Incorrect Answer Anions that contain oxygen, called oxyanions, use -ite as the suffix for anions with fewer oxygen atoms and -ate for anions with more oxygen atoms as in nitrite versus nitrate or chlorite and chlorate. The anion with one fewer oxygen atoms than the -ite anion uses the prefix hypo- as in hypochlorite, and the anion with one more oxygen atom than the -ate anion uses the prefix per- as in perchlorate. ClO4- Correct Answer Anions that contain oxygen, called oxyanions, use -ite as the suffix for anions with fewer oxygen atoms and -ate for anions with more oxygen atoms as in nitrite versus nitrate or chlorite and chlorate. The anion with one fewer oxygen atoms than the -ite anion uses the prefix hypo- as in hypochlorite, and the anion with one more oxygen atom than the -ate anion uses the prefix per- as in perchlorate.

Match the following terms with its definition. Drag and drop selections into the empty slot under the corresponding answer. Defines the identity of a particular isotope The average number of protons and neutrons in an atom, accounting for all known isotopes The total weight of 2 or more bonded atoms Defines the identity of an element Atomic number (Z) Defines the identity of an element Mass number (A) Defines the identity of a particular isotope Atomic weight The average number of protons and neutrons in an atom, accounting for all known isotopes Molecular weight The total weight of 2 or more bonded atoms

Correct Answer Explanation The atomic number (Z) is defined by the number of protons present in a nucleus, and it defines the identity of an element. The mass number (A) reflects the number of protons plus the number of neutrons, and it defines a certain isotope. Atomic weight can be thought of as a weighted average of the mass number across all naturally-occurring isotopes or as the average number of protons and neutrons in an atom. Molecular weight is the total mass of the atoms in a molecule.

Question 5 Which of the following atomic symbols represent ferrous and ferric ions, respectively? A Fe2+ and Fe3+ B Fe3+ and Fe2+ C Fe3+ and Fe+ D Fe2+ and Fe+

Correct Answer If a given element can be found in the form of more than one different cation, its charge will be indicated by a superscript numeral as in Fe2+ and Fe3+ or using Roman numerals as in iron(II) oxide vs. iron(III) oxide. Another option is for the ion with the lesser charge to have the suffix -ous and the ion with the greater charge with the suffix -ic as in ferrous ion and ferric ion.

Question 6 In a study of the various components of calcium halophosphate phosphor in their elemental forms, scientists identify Element A, with first, second, and third ionization energies of 1251.2, 2298, and 3822 kJ/mol, respectively, and Element B, with first, second, and third ionization energies of 589.8, 1145.4, 4912.4 kJ/mol, respectively. What are the most likely identities of Elements A and B? A. Element A = Ca, Element B = Cl B. Element A = Cl, Element B = O C. Element A = O, Element B = Cl D. Element A = Cl, Element B = Ca

D is correct. Based on the information in the question and the answer choices, we can observe that Element A shows a relatively even increase across these three ionization energies, while Element B shows a very sharp jump from the second ionization energy to the third ionization energy, suggesting that it is relatively easy to remove two electrons from it, but very difficult to remove a third. We can also observe that Cl is present in all four answer choices, so it must be one of the elements. Chlorine and oxygen are nonmetals located nearby in the periodic table, so it would not make sense for them to show such dramatically different behavior. That is, it is more likely that the other element is Ca. Element B is most likely to be Ca, because Ca is an alkaline earth metal that readily forms Ca2+ ions by losing two electrons, after which it reaches a stable noble gas configuration. A: This answer choice reverses Ca and Cl. B, C: Element A and Element B show two distinct patterns, so it is unlikely that they would both be nonmetals located next to each other on the periodic table, like O and Cl.

Question 11 Which of the following pure substances is a poor conductor of electricity? A. Mercury B. Lead C. Aluminum D. Iodine

D is correct. Metals are good conductors of electricity because their outer electrons can freely move between atoms. This movement of electrons is referred to as electrical current. Lead, mercury, and aluminum are all metals, while iodine is a nonmetal.

Question 2 Other gases and vapors can be used in lamps using the principles discussed in the passage. Which of the following elements would require the most energy to be discharged through the cathode? A. Mercury B. Sodium C. Sulfur D. Neon

D is correct. Since the first step of a fluorescent lamp is ionization, the correct answer to this question will be the element with the highest ionization energy. Within a given row of the periodic table, noble gases have the highest ionization energy, and ionization energies are higher toward the top of a column of the periodic table than toward the bottom. Combining these periodic trends, we can predict that neon will require the most energy to ionize. A, B, C: These elements have lower ionization energies than neon.

Question 13 The Bohr model's insistence on well-defined orbitals and predictable positions in space for electrons is most incompatible with: A. the Aufbau principle. B. the quantized nature of electronic transitions. C. the concept of effective nuclear charge. D. the Heisenberg uncertainty principle.

D is correct. The Bohr model depicts electrons orbiting the nucleus in discrete energy levels. Electrons preferentially fill less energetic shells first (according to the Aufbau principle), and the release or absorption of quantized amounts of energy is required to transition between these levels. The Bohr model also explains effective nuclear charge, since electrons farther away from the nucleus are shielded from the positive nucleus by the more interior electrons. However, the Bohr model suggests that electrons have well-defined, predictable orbits and positions, which is inconsistent with the Heisenberg uncertainty principle, which states that we cannot accurately know both the exact position and momentum of a given electron at once.

Question 15 How would 5 electrons be arranged in a p subshell? A All 5 electrons will be in their own orbital with parallel spin. B Three of the 5 electrons will share 2 orbitals with opposite spins. C Half of the electrons will have positive spin and half will have negative spin. D Two electron pairs will occupy two orbitals, and the remaining electron will be in the third orbital.

How would 5 electrons be arranged in a p subshell? A All 5 electrons will be in their own orbital with parallel spin. Incorrect Answer The p subshell only has 3 orbitals, so it is not possible for all 5 electrons to get their own orbital. B Three of the 5 electrons will share 2 orbitals with opposite spins. Incorrect Answer There are only two types of spin: positive and negative. This means it is not possible for all three electrons to have spins opposite to each other. Two of the three will have to have parallel spins (both negative or both positive) and the third can have opposite spin. C Half of the electrons will have positive spin and half will have negative spin. Incorrect Answer Half of 5 is 2.5, and it is not possible to have a fraction of an electron. Therefore, it does not make sense for half of the 5 electrons to have negative spin and half to have positive spin. Two electron pairs will occupy two orbitals, and the remaining electron will be in the third orbital. Correct Answer According to Hund's rule, one electron fills each orbital of a given subshell with parallel spin until each is half-filled, and then they begin sharing orbitals, or pairing, with another electron until the orbitals of that subshell are all filled. In this case, the first 3 electrons will each occupy their own orbital and the remaining two electrons will pair with an electron in the first two orbitals. This leaves two of the orbitals completely filled with two electrons each and the third orbital half-filled with one electron.

Match the following numbers with its description for the element oxygen. Drag and drop selections into the empty slot under the corresponding answer. Mass number Molecular weight found in nature Number of valence electrons Atomic number 6 Number of valence electrons 8 Atomic number 16 Mass number 32 Molecular weight found in nature

Oxygen has six valence electrons: 2 in the 2s orbital and 4 in the 2p orbital. The atomic number is determined by the number of protons in the element and is constant for that element. Oxygen has 8 protons, so its atomic number is 8. The mass number is the number of protons plus the number of neutrons. Oxygen has 8 protons and 8 neutrons, so its mass number is 16 amu. The atomic weight is the average weight of all isotopes of that element. The amount of oxygen with 8 neutrons vastly outweighs any other isotopes that exist, so the atomic weight is also 16 amu. The molecular weight is the sum of the weights of each atom that make up a molecule. Two oxygen atoms can combine to form diatomic oxygen gas, which is how oxygen is normally found in the environment. Each oxygen atom has an atomic weight of 16 amu, so the molecular weight is 32 amu.

Which of the following statements are true? Select all that apply. A Protons and neutrons are found in the nucleus. B Electrons reside with protons in the nucleus in order for the charges to cancel out. C It is unknown exactly where an atom's electrons are located at any given time. D Electrons make up the bulk of an atom's weight.

Protons and neutrons are found in the nucleus. Correct Answer This is true. B Electrons reside with protons in the nucleus in order for the charges to cancel out. Incorrect Answer Protons and neutrons are found together in the nucleus, and electrons are found orbiting the space around the nucleus. Electrons and protons do not need to be located together in order for their charges to cancel out. It is unknown exactly where an atom's electrons are located at any given time. Correct Answer Electrons exist in an electron cloud surrounding the nucleus, a volume of space where electrons are most likely to be found at any given time. We can't know with absolute certainty where within the electron cloud any particular electron is at a given time. D Electrons make up the bulk of an atom's weight. Incorrect Answer Electrons have a negligible mass compared to protons and neutrons. Therefore, protons and neutrons make up the atom's weight, not electrons.

Question 4 Which of the following best describes sodium after it has lost an electron? A Sodium becomes an anion with a -1 charge. B Sodium becomes an anion with a +1 charge. C Sodium becomes a cation with a -1 charge. D Sodium becomes a cation with a +1 charge.

Sodium becomes an anion with a -1 charge. Incorrect Answer Cations have positive charges and anions have negative charges. When sodium loses an electron, it loses a negative charge that was originally canceling out a positive charge from a proton. This will leave the atom with a +1 charge, making it a cation. B Sodium becomes an anion with a +1 charge. Incorrect Answer Cations have positive charges and anions have negative charges. Furthermore, when sodium loses an electron, it loses a negative charge that was originally canceling out a positive charge from a proton. This will leave the atom with a +1 charge, making it a cation. C Sodium becomes a cation with a -1 charge. Incorrect Answer Cations have positive charges and anions have negative charges. Furthermore, when sodium loses an electron, it loses a negative charge that was originally canceling out a positive charge from a proton. This will leave the atom with a +1 charge, making it a cation. Sodium becomes a cation with a +1 charge. Correct Answer Cations have positive charges and anions have negative charges. When sodium loses an electron, it loses a negative charge that was originally canceling out a positive charge from a proton. This will leave the atom with a +1 charge, making it a cation.

Question 1 Which of the following statements is true? A Some elements in the periodic table have no protons. B Protons and electrons have the same mass and opposite charges. C Neutrons have no charge and essentially no mass. D An electron carries a charge that is equal in magnitude to a proton.

Some elements in the periodic table have no protons. Incorrect Answer All elements in the periodic table contain at least one proton. B Protons and electrons have the same mass and opposite charges. Incorrect Answer While protons and electrons do carry opposite charges, their masses are not the same. A proton has a mass of 1 amu, and an electron has a far smaller mass. C Neutrons have no charge and essentially no mass. Incorrect Answer While neutrons have no charge, they do have a mass. A neutron has the same mass as a proton - about 1 amu. An electron carries a charge that is equal in magnitude to a proton. Correct Answer An electron carries an opposite charge that is equal in magnitude to a proton.

Masses

The correct order from smallest to largest mass is electron > proton > neutron. Electrons are the smallest subatomic particles because they have such a small mass, and it is considered negligible. Protons and neutrons both have a mass of 1 atomic mass unit (amu). Protons have a +1 charge and neutrons have no charge. Therefore, proton should be listed next, and neutron should be listed last.

Question 16 Which of the following elements have 10 electrons in their d subshell? Select all that apply. A Zinc (Zn) B Palladium (Pd) C Silver (Ag) D Roentgenium (Rg)

The electron configuration of zinc is [Ar] 4s23d10. B Palladium (Pd) Incorrect Answer The electron configuration of palladium is [Kr] 5s24d8. C Silver (Ag) Correct Answer The electron configuration of silver is [Kr] 5s14d10. Half-filled and fully-filled are more stable than subshells with any other number of electrons. So, a p subshell is especially happy with 3 or 6 electrons, and a d subshell is especially happy with 5 or 10 electrons, and so forth. This means there are a few exceptions to the Aufbau principle for electron configuration, particularly in the chromium and copper columns of the periodic table. Thus, copper has an electron configuration of [Ar] 4s13d10 because the 3d subshell steals an electron from the 4s orbital. Silver is in the same column as copper, so it will follow the same principle. D Roentgenium (Rg) Correct Answer The electron configuration of roentgenium (Rg) is [Rn] 7s15f146d10. Half-filled and fully-filled are more stable than subshells with any other number of electrons. So, a p subshell is especially happy with 3 or 6 electrons, and a d subshell is especially happy with 5 or 10 electrons, and so forth. This means there are a few exceptions to the Aufbau principle for electron configuration, particularly in the chromium and copper columns of the periodic table. Thus, copper has an electron configuration of [Ar] 4s13d10 because the 3d subshell steals an electron from the 4s orbital. Roentgenium is in the same column as copper, so it will follow the same principle.

The magnetic quantum number ml determines the number of orbitals and their orientation within a subshell. Consequently, its value depends on the orbital angular momentum quantum number l. Given a certain l, ml is an interval ranging from -l to +l, so it can be zero, a negative integer, or a positive integer.Jan 17, 2021 Quantum Numbers for Atoms - Chemistry LibreTexts https://chem.libretexts.org › ... › 10: Multi-electron Atoms About featured snippets• Feedback People also ask Does orbital angular momentum depend on magnetic quantum number? What is the relationship between the magnetic quantum number and the orbital angular momentum quantum number? The value of the magnetic quantum number is dependent on the value of the azimuthal (or orbital angular momentum) quantum number. For a given value of l, the value of ml ranges between the interval -l to +l. Therefore, it indirectly depends on the value of n.

The magnetic quantum number distinguishes the orbitals available within a subshell, and is used to calculate the The magnetic quantum number primarily determines the number of orbitals and the orientation of orbitals in a given sub-shell. Consequently, it is dependent on the orbital angular momentum quantum number, also known as the azimuthal quantum number. The angular momentum quantum number, signified by l, describes the general shape or region an electron occupies—its orbital shape. The value of l depends on the value of the principal quantum number, n. The angular momentum quantum number can have positive values of zero to (n−1).Apr 30, 2022

Question 7 Which of the following does an absorption spectrum depend on? Select all that apply. A The specific element B The movement of electrons from lower energy levels to higher energy levels C The movement of electrons from higher energy levels to lower energy levels D None of the above

The specific element Correct Answer Atomic emission and absorption spectra are unique for each element. The movement of electrons from lower energy levels to higher energy levels Correct Answer When an electron absorbs energy from any source, it jumps to a higher energy level. An electron can only absorb those wavelengths of light whose photons carry the exact amount of energy to match the energy gap between two levels (these need not be adjacent levels). As a result of this phenomenon, when a broad spectrum of visible light passes through a particular atom and its electron cloud, only certain wavelengths of this light are absorbed. An absorption spectrum is simply a list of those wavelengths that a particular element or material absorbs, usually presented graphically as the visible light spectrum with absorbed wavelengths denoted as black lines to indicate absorption. The movement of electrons from higher energy levels to lower energy levels Incorrect Answer This describes the process by which the emission spectra is generated. D None of the above Incorrect Answer Atomic absorption spectra are dependent on the specific element and formed because electrons can only jump between energy levels by absorbing or releasing energy.

Which of the following statements about valence electrons are false? Select all that apply. A Valence electrons tend to be the most tightly bound electrons in the atom. B Valence electrons interact with the electrons of other atoms. C Valence electrons are found farthest from the nucleus. D Chemical reactions are caused by the interactions of valence electrons between atoms.

Valence electrons tend to be the most tightly bound electrons in the atom. Correct Answer The question stem asks us to identify a false statement about valence electrons. Valence electrons are found in the outermost orbital; as such, they are in higher-energy orbitals and tend to be less tightly bound than those at lower energy levels. B Valence electrons interact with the electrons of other atoms. Incorrect Answer This is a true statement. The electrons in the outermost shell are called valence electrons, and these tend to be the ones responsible for interacting and reacting with other atoms' electrons. C Valence electrons are found farthest from the nucleus. Incorrect Answer This is a true statement. Valence electrons are found in the outermost electron shell, farthest from the nucleus. D Chemical reactions are caused by the interactions of valence electrons between atoms. Incorrect Answer This is a true statement. The interactions of valence electrons between atoms is what creates chemical reactions.

What is the electron configuration of Mg2+? A [Ne] B 1s22s22p63s2 C [Ne] 3s2 D [Ne] 3s23p2

What is the electron configuration of Mg2+? A [Ne] Correct Answer Mg2+ has two fewer electrons than neutral magnesium, giving the cation form the same electron configuration as neon (Ne). We can abbreviate the electron configuration by placing the last element of the prior row in brackets to represent its electron configuration, and then add the configuration of the valence electrons from the periodic table. Mg2+ has lost its two valence electrons, so there is nothing to follow [Ne]. B 1s22s22p63s2 Incorrect Answer This is the long-hand notation for neutral magnesium. The magnesium cation Mg2+ has lost two electrons in the 3s subshell. [Ne] 3s2 Incorrect Answer This is the short-hand notation for neutral magnesium. The electron configuration of the magnesium cation Mg2+ has lost two electrons in the 3s subshell. D [Ne] 3s23p2 Incorrect Answer This is the shorthand notation for a hypothetical anionic form of magnesium, Mg2- or of silicon (Si). We can't tell which atom the electron configuration belongs without knowing the number of protons involved or the charge on the element.

Which of the following situations would NOT occur under the Pauli exclusion principle? A One electron in the 4s subshell and 5 electrons in the 3d subshell B Four electrons in the 2p subshell C An electron in the 1s subshell with positive half spin and the other with negative half spin D Two electrons in the 1s subshell with positive half spin

Which of the following situations would NOT occur under the Pauli exclusion principle? A One electron in the 4s subshell and 5 electrons in the 3d subshell Incorrect Answer Having one electron in the 4s subshell and 5 electrons in the 3d subshell does not violate the Pauli exclusion principle and is the electron configuration for chromium. B Four electrons in the 2p subshell Incorrect Answer Having 4 electrons in the 2p subshell does not violate this principle. Four electrons can still occupy different orbitals and have different half spins. C An electron in the 1s subshell with positive half spin and the other with negative half spin Incorrect Answer An electron in the 1s subshell with positive half spin and the other with negative half spin conforms to the Pauli exclusion principle, since these two electrons will have different spin quantum numbers. Two electrons in the 1s subshell with positive half spin Correct Answer According to the Pauli exclusion principle, no two electrons in a given atom can have the exact same four quantum numbers. Two electrons in the 1s subshell with positive half spin would have the exact same four quantum numbers: 1, 0, 0, +1/2.

Which of the following statements accurately describes Ca2+? Select all that apply. (Refer to the periodic table if necessary.) A It has 20 protons, 20 neutrons, and 20 electrons. B Its mass number is 40 amu. C It has two fewer neutrons than Ca. D It has 20 protons and 18 electrons.

Which of the following statements accurately describes Ca2+? Select all that apply. (Refer to the periodic table if necessary.) A It has 20 protons, 20 neutrons, and 20 electrons. Incorrect Answer This calcium cation carries a 2+ charge, so there should be two fewer electrons than protons. B Its mass number is 40 amu. Correct Answer Calcium has an atomic number of 20 which indicates this atom has 20 protons. There is no fixed rule for predicting the number of neutrons in the nucleus of the atom, so it is necessary to consult the periodic table to determine the atomic weight of calcium. The value of 40.08 indicates that the overwhelming majority of calcium atoms have a mass number of 40 amu, corresponding to 20 neutrons. C It has two fewer neutrons than Ca. Incorrect Answer This particular calcium cation carries a 2+ charge, so there should be two fewer electrons than protons. It has 20 protons and 18 electrons. Correct Answer This particular calcium cation carries a 2+ charge, so there should be two fewer electrons than protons. There are 20 protons in a calcium atom, so this cation will have 18 electrons. Calcium atoms generally contain the same number of protons and neutrons (20 each).

Question 3 Which of the following statements most accurately describes the relationship between orbital radius and electron energy? A Electrons in lower energy levels are more tightly bound. B The closer to the nucleus, the lower an energy level an electron is occupying. C Electrons are at higher energy levels closer to the nucleus. D Valence electrons are at the lowest energy level.

Which of the following statements most accurately describes the relationship between orbital radius and electron energy? A Electrons in lower energy levels are more tightly bound. Incorrect Answer While this is a true statement, it does not explain the relationship between orbital radius and electron energy. The closer to the nucleus, the lower an energy level an electron is occupying. Correct Answer Electrons in orbitals closest to the nucleus are at the lowest energy level and the most stable. C Electrons are at higher energy levels closer to the nucleus. Incorrect Answer Electrons in orbitals closest to the nucleus are at the lowest energy levels. D Valence electrons are at the lowest energy level. Incorrect Answer Valence electrons are found in the outermost orbital, which means they have a large orbital radius and would be at the highest energy level of any occupied orbital in the absence of excited electrons.

Question 13 What is the electron configuration of beryllium (Be)? Select all that apply. A [Li] 2s2 B [H] 1s22s2 C [He] 1s22s2 D 1s22s2

[Li] 2s2 Incorrect Answer We can abbreviate the electron configuration by placing the last element of the prior row in brackets to represent its electron configuration, and then add the configuration of the valence electrons from the periodic table. Lithium [Li] is not the last element from the prior row, so it should not be in brackets. B [H] 1s22s2 Incorrect Answer We can abbreviate the electron configuration by placing the last element of the prior row in brackets to represent its electron configuration, and then add the configuration of the valence electrons from the periodic table. Hydrogen [H] is not the last element from the prior row, so it should not be in brackets. [He] 1s22s2 Incorrect Answer We can abbreviate the electron configuration by placing the last element of the prior row in brackets to represent its electron configuration, and then add the configuration of the valence electrons from the periodic table. Electrons in the 1s subshell are not valence electrons for beryllium, so they should not be included in this shorthand version of beryllium's electron configuration. D 1s22s2 Correct Answer Beryllium has 4 protons, as indicated by its atomic number, so neutral beryllium should have 4 electrons. This is the only answer choice that accounts for 4 electrons and is written in proper notation.

Electron affinity

amount of energy released when elec added to an atom, more readily accept elec like halogens = higher EA addition of elec is exothermic, energy released EA negative when elec is accepted, if energy added to produce an anion, EA is positive halogens: readily accept an elec, high negative EA, gaining elec is stabilizing Be: positive EA, gaining elec is destabilizing EA = directly related to Zeff, more positive nuclear charge = greater affinity for electrons, top right of periodic table = higher EA values, exception: noble gases, zero EA have full valence shells

EN

atom attracts elec shared in a chemical bond, high EA naturally attract elec more strongly EN related to Zeff directly, EN relates to behavior within a chemical bond EN inc left to right along a period as radius decreases across decreases down a group increase in n and shielding effect, causes elec to have lower electrostatic attraction to nucleus Fluorine on top right = most EN element Zeff, EA, EN, IE, electrostatic attraction, nuclear charge are all increasing across a period, decreasing principal quantum number (n), atomic radius and shielding effect same number of valence shells across a period EA, IE, EN, Zeff, Elec attraction, nuc charge are all decreasing down a group (higher at the top) n, atomic radius, shielding effect, number of valence shells for core elec are all increasing down a group

Question 8 Which of the following is true about the energy associated with an electron moving from orbital n = 5 to n = 2? (Note, R = 2.18 x 10-18J) A 4.6 x 10-19 J is absorbed B 4.6 x 10-20 J is absorbed C 4.6 x 10-17 J is emitted D 4.6 x 10-19 J is emitted

if energy emitted, value is negative and energy level has decreased ans is D 2.18(10^-18 * (-21/100) = -4.6 * 10^-19

Heisenbergy uncertainty

impossible to know exact position of electron and momentum of electron at the same time electrons are located in orbitals, four quantum numbers to describe position, principal quantum number: n: Bohr radii energy level of electron higher n= greater energy, greater the distance from nuc, periodic table arranged in row = inc values of n shape of orbital orientation angular momentum azimuthal (l): shape of an orbital's subshell. own characteristic orbital shapes, s= spherical p=dumbbell shaped d and f orbitals: more complex 1 s, 3 p, 5 d and 7 f orbitals in total shapes for different subshells ml (magn quantum number): spatial orientation of orbital region of space with respect to an applied magnetic field

Shielding effect

inner electrons shield outer elec from nucleus, electrostatic attraction between nuc and outer elec decreases, shielding effect is lower across the row, valence elec shield each other poorly

shielding effect:

inner electrons shield outer elec from nucleus, electrostatic attraction between nuc and outer elec decreases, shielding effect is lower across the row, valence elec shield each other poorly down a group: shielding effect is signifcant H has no shielding effect so Z = Zeff, for all others Zeff <Z more electrostatic attra : less shielding effect for valence elec from nuclear charge, high Zeff, less layers/same shells of core elec the principal quantum number increases, more layers of core elec shield valence elec from positive nuclear charge, Z eff decreases as one moves down a group more shielding due to more layers of core elec from positive nuclear charge, significant shielding effect down a group = decreasing Zeff less tightly held valence elec shielded from core, down a group, decreasing electrostatic attrraction between nucleus and outer electrons, significant shielding effect down a group when inner elec shielding outer elec from nuc nuclear charge increases across a period, electrostatic force increases, more tightly held due to more electrostatic interaction?? poor shieldng = less shielding effect across a row Zeff increases number of protons and elec increases nuclear charge remains stable down a group?

Question 10 Which of the following are possible values for angular momentum quantum numbers in the n = 4 shell? A +1/2, -1/2 B 0, 1, 2, 3 C -3, -2, -1, 0, 1, 2, 3 D -1, 0, 1

magnetic quantum numbers: neg l to positive l for a subshell, possible orientation in space for this subshell angular momentum quantum number l: 0 to n-1 for a given principal quantum number, shape of orbital, which subshell elec is located within a shell, s (l=0), p (l=1), d (l=2), f (l=3) +1/2, -1/2 Incorrect Answer This answer choice lists possible spin quantum numbers, not angular momentum quantum numbers. B 0, 1, 2, 3 Correct Answer The angular momentum quantum number (l), also called the azimuthal quantum number, describes the shape of the orbital. This tells us what subshell the electron is located in within a shell, where L can range from 0 to n-1 for a given principal quantum number. A shell of n = 4 will have angular momentum quantum numbers 0 to 3 which includes 0, 1, 2, and 3. -3, -2, -1, 0, 1, 2, 3 Incorrect Answer The angular momentum quantum numbers do not include negative values. These values describe the magnetic quantum numbers which range from negative l to positive l for a given subshell. D -1, 0, 1 Incorrect Answer The angular momentum quantum numbers do not include negative values. These values describe the magnetic quantum numbers, which range from negative L to positive L for a given subshell. In this case, the values represent the p subshell.

Pauli exclusion principles

no two electrons in a given atom can have exact same value for all four quantum numbers

low boiling points and gases at room temp

noble gases

Ionization energy: energy to remove one valence elec from neutral atom in gaseous state

positive, requires input of energy to remove an elec from nucleus IE 1: required to remove one elec from neutral atom is smaller than IE 2 (to remove 2nd elec),elec removed from positively charged species IE directly related to Zeff, atoms with higher Zeff = need more energy to remove elec that are tightly held IE increases as one moves up aand to the right across half filled 2 p subshell for N is more stable bc no paired elec, difficult to remove valence elec from N than from Oxygen, an additional 2 p elec (loses easily) higher increase in IE when removing elec from half filled or filed stable subshell N = has higher first IE than the second imp to visualize elec config and subshell

Ionic radius

radius of charged species ions, cations: smaller iionic radius than atomic radius of neutral atom, elec -elec respulsions lowered when elec removed from valence shell, remaining valence elec experiences greater positive charge anions: ionic radius larger than corresponding atomic radius, more avelnce electrons added increase electrostatic repulsions average nuclear attractice force decreases (less tightly held), ionic radius is larger for anion than for neutral atom pair trends with an element example

number of valence electrons number of valence shells

rows/periods, coefficient (n), number of valence elec increases until valence shell is full until noble gas/full electron shell, number of elec and protons in nuc increases across a period, electrostatic force increases, Z eff also increases groups, same number of valence elec, more number of elec shells or principal quantum number increases, more layers of core elec, share same physical and chemical properties, donate or gain elec to achieve stability (full valence shells), the principal quantum number increases, more layers of core elec shield valence elec from positive nuclear charge, Z eff decreases as one moves down a group [noble gas] = electron config of inner shell elec for ions add/remove charge from highest energy subshell first (highest principal quantum number n) electrons fill valence s orbital before d orbital electrons removed from valence s orbital first, filled from lowest energy to highest energy 4s fills before 3d 4s subshell = higher in energy than 3d, 4s electrons are lost first for cations more stable if half filled or gully filled, minimize electron electron repulsions if half filled or all elec are spin paired, more stable than subshells with less number of electrons, half filled more energetically favorable Cr and Cu exceptions*** elec config: more energetically stable for Cr = if s elec promoted to the d orbital, two half filled orbitals and more stable arrangement. elec config Cr = [Ar] 4s1 3d5 Cu: [Ar] 4s1 3d10, half filled and filled subshells