Chemistry (Chapter 3)

How many electrons can an f subshell hold?

14

What is the electron configuration of K+?

1s22s22p63s23p6 [Ar] First, identify the electron configuration of the neutral atom K, which is 1s22s22p63s23p64s1. Since K+ is a cation, the electron configuration of K+ has one less electron than that of K. This means one electron needs to be removed from the outer shell, giving the configuration, 1s22s22p63s23p6. This configuration is the same as the noble gas [Ar], which makes the K+ cation quite stable.

Which would be an invalid listing within an electron configuration?

2d^5

In an orbital diagram, such as the one below, each small box represents which of the following?

Each box represents an individual orbital, each of which can hold two electrons.

Which set of quantum numbers is invalid?

n=0,l=0,ml=0,ms=1/2 The principal quantum number, n, must be at least 1.

The visible lines on hydrogen's emission spectrum all result from electron transitions ending in what n value? - Report your answer as an integer (whole number) without any decimal places.

n=2 The visible lines in hydrogen's emission spectrum are called the Balmer series, which all have a final n value of 2.

Which of the following species has the smallest radius? C4+ B3+ Be2+ Li+

C4+ These species are isoelectronic, and carbon has the most protons, so it will attract the remaining two core electrons the most.

Which of the following has the lowest electron affinity? Ca N In Ge

Ca would have the lowest electron affinity because Group 2A has a filled ns subshell. It does not follow the expected trend.

The 5p orbitals fill immediately after the 4d orbitals and immediately before the 6s based on: (select all that apply)

- Observed experimental results - Theoretical calculations The 5p orbitals fill immediately after the 4d orbitals and immediately before the 6s based on observed experimental results, and has been supported by theoretical calculations.

What are the core electrons in phosphorus?

1s22s22p6

According to the Aufbau rule, what is the electron configuration of iron?

1s22s22p63s23p64s23d6

Which subshell holds the valence electrons of barium?

Barium is in group 2, which is in the s block, and it is in period 6, so the 6s subshell is the only subshell with valence electrons.

Who demonstrated that white light actually consists of the individual colors of the rainbow?

In the 17th century, Isaac Newton worked with lenses and prisms to demonstrate that white light consists of all the different colors of visible light.

Most exceptions to the trend of decreasing radius moving to the right within a period occur in the __________.

In the d block, there is some slight deviation in terms of covalent radius moving to the right along a period.

How many valence electrons are there in a neutral atom of potassium (K). Enter the answer as a whole number.

K:1s22s22p63s23p64s1 The valence electrons for the main group elements are those of the highest n value, in this case, the electron in 4s. This means K has 1 valence electron.

How many electrons are located in the highest energy orbital of aluminum? Al electron configuration=1s22s22p63s23p1

Looking at this electron configuration we see that 3p is the highest energy orbital. If we then look at the superscript attached to it, we see that it contains 1 electron.

What is the symbol for the following ion electronic structure: [He]2s22p6 with an atomic number of 12?

Mg2+ Atomic number 12 corresponds to Mg but there are 2 less electrons than Mg usually has (lost electrons = cation) so: Mg2+.

Which set of quantum numbers is invalid? n=3,l=1,ml=0,ms=−12 n=1,l=0,ml=0,ms=12 n=5,l=3,ml=−3,ms=−12 n=2,l=0,ml=−1,ms=12

Since l =0 indicates a s-orbital (sphere-shaped), there are no additional vector directions and the magnetic quantum number ml must also be zero. Therefore, the option n=2,l=0,ml=−1,ms=12 does not represent a valid set of quantum numbers.

Which of the following signifies the spatial orientation, i.e. direction, of an atomic orbital?

The magnetic quantum number, ml, signifies the spatial orientation of an atomic orbital.

Which quantum number does NOT give information about an individual orbital?

The spin value will not describe an individual orbital, as any electron in any orbital will simply have a spin of 12 or −12.

The electrons in the outermost shell of an atom are called:

The valence electrons of an atom are those in the outermost shell, which are available for bonding or ionization.

What is the abbreviated electron configuration of yttrium (Y)?

[Kr]5s24d1 The noble gas from the row above is krypton, so we will need krypton core plus the valence electrons in the 5s and 4d orbitals.

What is the abbreviated electron configuration of silicon?

[Ne]3s23p2 The noble gas from the row above is neon, so we will need neon core plus the valence electrons 3s2 and 3p2.

What is the abbreviated electron configuration of cesium?

[Xe]6s1

An electron in an unknown energy level of a hydrogen atom transitions to the n=2 level and emits a photon with wavelength 410 nm in the process. What was the initial energy level?

λ=hc/E 410 nm×1 m/10^9 nm=4.10×10^−7 m E=hc/λ E=(6.626×10^−34 Js)(2.998×10^8ms)/4.10×10^−7 m E=4.845×10^−19 J ΔE=RH(1/n2f−1/n2i) 1/4−1/n2i=4.845×10^−19 J/2.18×10^−18J=0.2223 0.25n2i−1=0.2223n2i 0.25n2i−0.2223n2i=1 0.0277n2i=1n2i=10.0277=36.1ni=6.008 -> 6

Which of the following isoelectronic particles has the smallest radius? Ca2+ K+ Ar Cl−

Ca2+ Isoelectronic particles all have the same number of electrons but differing number of protons. As the number of protons increases in the series, an increasing nuclear charge is being exerted on the same number of electrons. This means that valence electrons are pulled closer as the number of protons increases. Ca2+ has the greatest number of protons at 20 and will therefore have the smallest radius.

Which core electrons are implied by the symbol [He]? Write the configuration for the core electrons.

Helium has an electron configuration of 1s2, so these are the core electrons that are implied when an element is listed as having a helium core.

The orbitals that are next highest in energy after the 4s orbital are the:

3d

The orbitals that are next highest in energy after the 5s orbitals are the

4d The d orbitals are one behind the period number in terms of principal quantum number.

The orbitals that are usually the next highest in energy after the 6s orbitals are the:

4f

How many valence electrons does an iron atom ( Fe) have?

8 Recall that transition metals don't have "traditional" valence electrons. The valence electrons for a transition metal element are those of the highest ns and n−1d value, in this case those electrons in 4s and 3d. This means Fe has 8 valence electrons.

The view of light that describes light as consisting of particles is called:

A corpuscle refers to a tiny particle, hence the view that light consists of particles is the corpuscular view of light.

Which element, when it loses 3 electrons, will have the electron configuration 1s22s22p6?

Aluminum is the third element in period 3 so when it loses three electrons it will have neon electron configuration.

What is the symbol for the following ion electronic structure: [Ne]3s23p6 with an atomic number of 16?

Atomic number 16 corresponds to S but there are 2 more electrons than S usually has so we know that S had to gain (−2).

Which of the following is the correct sequence for increasing order (i.e., smallest to largest) of first ionization energy (IE)?

Atoms with half-filled or completely filled orbitals in the outer shell are more stable and possess higher IE. As atomic radius increases, IE decreases. Although B is smaller than Be, we expect the Be atom to have a higher IE because of the stable 2s2 configuration. N's 1s22s22p3 configuration is more stable than the 1s22s22p4 configuration of O, so N has a greater IE than O. The correct answer choice is B<Be<O<N.

Which will NOT have an abbreviated electron configuration beginning with the argon core?

Chlorine is before argon on the periodic table, so it does not have all the electrons argon has in its ground state. We will abbreviate chlorine by using the neon core.

What is the configuration for the valence electrons in chlorine? Do not include the core electrons in the configuration.

Chlorine's full electron configuration is: 1s22s22p63s23p5. The valence electrons are those in the highest energy level, in this case the 3s23p

The realm of physics that described light as having strictly wave-like character is called:

Classical electrodynamics is based on Maxwell's equations, which assume that light behaves as a wave.

For a particular energy level, removing an electron from the __________ subshell would require a higher first ionization energy.

Comparing the energies of the s and p subshells within a given energy level (n), it is more difficult to remove an s electron. For any given value of n, the s subshell has a lower energy than the p subshell, so IE1 is higher for an s electron within that principal energy level.

Orbitals that have the same energy are called:

Degenerate is the word we use to refer to orbitals that have identical energy, such as the orbitals inhabiting the same subshell.

If the electron affinity for an element is negative, this means that

Electron affinity (EA) is defined as the energy change for the process of adding an electron to a gaseous atom to form an anion (negative ion). Therefore, If the electron affinity for an element is negative, this means that energy is released when an atom gains an electron. In other words, a negative value for the electron affinity means that the process of gaining an electron is exothermic, and is an energetically favorable process.

Which of the following is a rule indicated by the Aufbau principle?

Electrons are placed in the lowest energy subshell that is not fully occupied.

Electrons in orbitals that experience shielding:

Electrons in orbitals that experience shielding are less stabilized and have higher energy.

Elements that have similar electron configurations belong to the same:

Elements in the same group have the same number of valence electrons, so they will be housed in orbitals in a similar way. Thus, they will have similar electron configurations.

What will be the wavelength of a photon that is emitted when an electron of a hydrogen atom undergoes a transition from n=7 to n=4?

First, determine the energy change for the transition from ni=7 to nf=4 using the Rydberg equation ΔE=−RH(1n2f-1n2i) = −2.18×10−18J(1/4^2−1/7^2) = −2.18×10−18×(0.0625−0.020408) ≈−9.1718×10−20J Photons only have positive energies. That ΔE is negative means that the electron loses energy by emitting a photon with 9.1718×10−20J, rather than gaining energy by absorbing a photon. Now, use Planck's equation to determine the wavelength of the photon emitted during this transition. ΔE=hc/λ -> λ=hc/ΔE ≈(6.626×10^−34J s)(2.998×10^8ms)/9.1718×10^−20J =2.1658×10^−6 m -> 2.17×10^−6 m

Which of the following species has the largest radius? O2− F− Ne Na+

For any series of isoelectronic particles, the radius decreases as the atomic number (the number of protons) increases. Note that all of these species are isoelectronic with neon, meaning they all have the same number of electrons. Oxygen has the least number of protons of the species listed (smallest atomic number). Therefore, the electrons in O2− will be the least attracted to the nucleus, and so this ion has the largest radius

The electron configuration for sodium is 1s22s22p63s1. Which subshell is said to contain the valence electron(s) for sodium?

For main group elements, the shell with the largest value of n is called the valence shell. In this case, the subshell with the largest value of n is the 3s subshell (n=3), and so the single valence electron in sodium is held in the 3s subshell.

Which of the following elements has the lowest ionization energy? H Li Na Fr

Francium, being the largest element and having only one electron in its valence shell, will require the least amount of energy to ionize.

The core electrons in most elements can be represented by a noble gas configuration. For example, the abbreviated electron configuration for sodium is written as [Ne]3s1, where [Ne] represents the core electrons in the 1s, 2s, and 2p subshells. Which element will not have an abbreviated electron configuration beginning with a noble gas configuration?

Hydrogen does not have all the electrons that helium does in its ground state, so hydrogen can not be abbreviated at all, it must be listed as 1s1.

Calculate the change of energy for an electron within a hydrogen atom that undergoes a transition from n=3 to n=4. - Use RH=2.18×10^−18J for the Rydberg constant. - Report your answer in scientific notation. Use the multiplication symbol rather than the letter x in your answer. - Your answer should have three significant figures

In this case, the electron starts out with n=3, so ni=3. It comes to rest in the n=4 orbit, so nf=4. The difference in energy between the two states is given by the following expression: EΔ= Ef−Ei = −(2.18×10^−18 J)(1/n2f−1/n2i) EΔ= −(2.18×10^−18 J)(1/4^2−1/3^2) EΔ= −(2.18×10^−18 J)(1/16-1/9) EΔ= 1.06×10^−19J

Which of the following has the last electron added into the f orbital?

Inner transition elements are metallic elements in which the last electron added occupies an f orbital. The valence shells of the inner transition elements consist of the (n - 2)f, the (n - 1)d, and the ns subshells. FEEDBACK

Which of the following phenomena can only be explained by considering the wave nature of light?

Interference

Which of the following species is expected to have the smallest radius? S2− Cl− Ar K+

K+ These species are isoelectronic, and potassium has the most protons, which means its nucleus exerts the greatest attraction on the electrons.

Which element has the core electrons 1s22s22p6?

Na. Sodium has one valence electron in the 3s orbital, so all the electrons that have n=2 or less can be considered core electrons.

Which core electrons are implied by the symbol [Ne]? Enter your answer in electron configuration format.

Neon has the electron configuration 1s22s22p6, so these are the core electrons that are implied when an element is listed as having a neon core.

Deviations to the trends in first ionization energy occur because of which of the following?

Orbital symmetry For example, oxygen has a slightly lower ionization energy than nitrogen because nitrogen would lose half-full p orbitals while oxygen would gain half-full p orbitals. The enhanced stability of this orbital symmetry is responsible for the deviation from the trend for these two elements.

The more electrons an atom has the more __________________ it will need.

Orbitals An orbital is a region of probability where an electron can be found. There are s, p, d, and f orbitals, and each one has a different shape. The orbitals have different shapes to show the regions in space where electrons can be found. Each orbital can hold 2 electrons, the more electrons an atom has, the more orbitals it will need to accomodate them all.

The Aufbau principle states that:

Orbitals will be filled in order of increasing energy, which is generally in order of increasing principal quantum number.

Each row on the periodic table corresponds to which quantum number for s and p orbitals?

Principal quantum number The period or row number corresponds to the n value which is the principle quantum number for the orbital subshells. Therefore, elements in row 1 fill the 1 s orbital. Elements in row 2 begin to fill the 2 s and 2 p orbitals, and so on. Notice though, that when the d and f subshells begin these start at n−1 and n−2, respectively.

Which will have an abbreviated electron configuration beginning with the radon core?

Pu. Plutonium is on the row immediately after radon, so we abbreviate it as radon core, plus the valence electrons for plutonium.

Covalent radius increases as we move __________ on the periodic table.

Radius increases down the periodic table as we add more shells and left as the effective nuclear charge decreases.

Which element, when it gains two electrons, will have the electron configuration 1s22s22p63s23p64s23d104p6?

Selenium (Se) has an electron configuration of 1s22s22p63s23p64s23d104p4. If it gains two electrons, it will have the same electron configuration as krypton (Kr).

What is the electron configuration for the valence electrons in strontium? Do not include the configuration of the core electrons in your answer.

Strontium's full electron configuration is 1s22s22p63s23p64s23d104p65s2. Krypton has the electron configuration 1s22s22p63s23p64s23d104p6. These core electrons are stable and do not take part in bonding, while the remaining electrons are valence electrons. Therefore, the configuration for the valence electrons in strontium is 5s2.

What are the core electrons of strontium?

Strontium's full electron configuration is 1s22s22p63s23p64s23d104p65s2. To find its core electrons, we must separate the valence electrons (in this case, 5s2) from all of the complete principal energy level shells (the configuration of the closest noble gas). Thus we isolate the electron configuration of krypton, 1s22s22p63s23p64s23d104p6, from the full electron configuration of Sr. These are its core electrons, which are virtually unreactive as they constitute full octets.

The order in which orbitals are listed on an orbital diagram follows:

The Aufbau principle

What is the electron configuration for Cl−?

The Cl anion gains 1 electron so 1s22s22p63s23p6 from 1s22s22p63s23p5

What is the electron configuration for Zn2+?

The Zn cation loses 2 electrons to form Zn2+. The electron configuration of Zn is 1s22s22p63s23p64s23d10. Note that because zinc is a transition metal, it will lose the 4s electrons before the 3d electrons. Therefore, the electron configuration of Zn2+ is 1s22s22p63s23p63d10.

In which of the following element blocks does the atomic radius generally not tend to increase when moving down within a group?

The atomic radius generally increases when going down a group in all of the above element blocks. In every group, the atomic radius will increase as we move down the table, without exception. This is because each lower period features atoms with an additional shell, and that additional shell is farther from the nucleus.

In order to solve the photoelectric effect, Einstein applied quantization to which parameter?

The behavior of light. Einstein's solution required that light be viewed as particles, or quanta, rather than continuous waves.

Increasing the _______ of incoming light can cause an increase in the number of ejected electrons.

The brightness of incoming light, or the number of photons striking the surface within a given time period, can cause an increase in the number of ejected electrons.

What is the configuration for the valence electrons in cobalt's electron configuration? Do NOT include the configuration of the core electrons in your answer.

The complete electron configuration of cobalt is 1s22s22p63s23p64s23d7. This configuration includes the argon core ([Ar]:1s22s22p63s23p6). These electrons are core electrons because they are stable and do not take part in bonding. The remaining electrons are called valence because they do take part in bonding. Therefore, the configuration for the valence electrons for cobalt is 4s23d7.

The electrons most responsible for shielding in an atom are the __________.

The core electrons shield the valence electrons from the nuclear charge because they are positioned between the protons and the valence electrons.

The electrons occupying the innermost shell orbitals are known as:

The electrons occupying the innermost shell orbitals are known as core electrons.

The greater the frequency of the photon that strikes a metal:

The greater the kinetic energy of an ejected electron. Only one electron will be ejected by a particular photon. Above the threshold frequency, a higher frequency means more kinetic energy imparted onto the ejected electron.

Which of the following labels are used for quantum numbers to describe the state of an electron inside an atom? Select all that apply.

The magnetic quantum number (ml), the spin quantum number (ms), the principal quantum number (n), and the angular momentum quantum number (l) all describe electrons within atoms. (m) and (mo) are not labels used to describe the state of an electron in an atom.

Which of the following quantum numbers describes an electron in an atom? Select all that apply.

The magnetic quantum number (ml), the spin quantum number (ms), the principle quantum number (n), and the angular momentum quantum number (l) all describe an electron.

Which of the following have the last electron added in an s or p orbital?

The main group elements have the last electron added in an s or p orbital. The transition metals and inner transition metals have the last electron added in a d or f orbital, respectively.

If above the threshold frequency, the brighter the source of light:

The more electrons that will be ejected. Brighter light means more photons, which means more photons will strike electrons and eject them.

Before the work of Albert Einstein and other prominent scientists of the early 1900's, the predominant view among physicists was that light is:

The predominant view before Einstein's work with the photoelectric effect was that light is wave. Scientists now recognize that light can behave as both a particle and a wave.

Which of the following increases with increasing energy?

The principal quantum number and the angular momentum quantum number increase with increasing energy.

Which set of quantum numbers is invalid? n=1,l=1,ml=0,ms=12 n=2,l=0,ml=0,ms=−12 n=3,l=1,ml=0,ms=12 n=2,l=1,ml=−1,ms=−12

The principle quantum number is n. The angular momentum quantum number, l, must be an integer from 0 to n−1, inclusive. The magnetic quantum number, ml, must be an integer between −l and l, inclusive. Therefore, l must be less than n, so the set of quantum numbers, n=1,l=1,ml=0,ms=1/2, is invalid.

The electron affinity trend is:

The same as the ionization energy trend but opposite the atomic radius trend The higher the ionization energy, the more difficult it is to lose an electron, and therefore usually the easiest it is to add an electron, so the ionization energy and electron affinity trends are parallel. These trends are both opposite the atomic radius trend, as a larger radius means lower ionization energy and electron affinity.

The electron affinity (EA) is the energy change for the process of adding an electron to a gaseous atom to form an anion (negative ion). Which of the following is true about the electron affinity?

The sign of the electron affinity depends on the element. For most elements, the process of adding an electron to a gaseous atom to form an anion (negative ion) is exothermic, which means that energy is released when the gaseous atom accepts an electron. However, for some elements, energy is required for the atom to become negatively charged and the value of their EA is positive

Who did experiments with light , known as the double-slit experiments, to produce interference patterns that could only be explained by evoking a wave-like nature for light?

Thomas Young was the first to perform the double slit experiments. The experiment involved passing light through two tiny slits, thereby producing an interference pattern that could not be reconciled with the corpuscular view of light. Thus, the findings of Thomas Young supported the hypothesis that light consists of waves rather than particles.

Identify the element from the electron configuration: [Ar]4s23d2.

Ti

Identify the element with the lowest electron affinity based on periodic trends. Sr Na F P

Using the periodic table and knowing that the electron affinity generally increases as we move from left to right and bottom to top, we can determine that Sr would have the lowest electron affinity.

Valence electrons:

Valence electrons are in the highest energy level and generally participate in the formation of chemical bonding. -Are lost first - Available to do the chemistry and participate in covalent bonding - Highest energy

Which of the following is a form of electromagnetic radiation?

Visible light is a form of electromagnetic radiation. Visible light and other forms of electromagnetic radiation are important because they can be used to infer the energies of electrons within atoms and molecules.

When constructing electron configurations for ions, we ______ electrons for a negative ion.

When constructing electron configurations for ions, we add electrons for a negative ion.

Hund's rule states that:

You must place one electron in each orbital in a subshell before doubling up.

Which of the following has a decrease in Zeff, given that the number of protons remains the same? Great work! That's correct.

Zeff is the effective nuclear charge, the charge that leads to the Coulomb force exerted by the nucleus on an electron, calculated as the nuclear charge minus shielding. The addition of one or more electrons to the valence shell with the same number of protons present leads to a decrease in Zeff.

A certain kind of light has a wavelength of 4.6 μm (micrometers). What is the frequency of this light in GHz? - Use c=2.998×108ms for the speed of light. - Your answer should have two significant figures.

c =λ⋅ν - 4.6μm×(1.0 m10.6 μm)=4.6×10−6 m ν=cλ - ν=2.998×108ms4.6×10−6 m=6.517×1013s−1 6.517×1013 Hz(1.0 GHz1.0×109 Hz)=6.517×104 GHz -> 6.5×104 GHz.

Electrons that inhabit different orbitals must have a different value for the:

none of the above They could have the same principal quantum number if they are in different orbitals with the same shell, they could have the same angular momentum quantum number if they are in different orbitals of the same type of subshell, and they could have the same spin value, as every full orbital will have one electron spin up and one spin down.

What is the maximum wavelength of photon that will eject a ground state electron from a hydrogen atom? - Report your answer in scientific notation. Use the multiplication symbol rather than the letter x in your answer. - Your answer should have three significant figures.

ΔE=hc/λ= −2.18×10^−18 J×[1n22-1n21] (6.626×10^−34)(3×10^8)/λ = −2.18×10^−18 J×[1/∞-1/1] 1.9878×10^−25/λ = −2.18×10^−18 J×(0-1) λ = 9.13×10^−8 m