General Chemistry Chapter 1: The Atomic Structure

What is the relationship between energy and wavelength?

Inversely proportional, the higher the wavelength, the smaller the energy and vice versa.

What does diamagnetic mean?

Materials slightly repelled by a magnetic field because they only have paired electrons/

Atoms of the same element have the same atomic number, but what contributes to the different mass numbers?

Neutrons! Different atoms of the same element can have different numbers of neutrons. Protons always stay the same.

Determine the number of protons, neutrons, and electrons in a nickel-58 atom and in a nickel-60 +2 cation.

Nickel-58: 28 protons, 28 electrons , 30 neutrons Nickel - 60: 28 protons, 26 electrons, 32 neutrons

In nuclear medicine, isotopes are created and used for various purposes; for instance, 18O is created from 18F. Determine the number of protons, neutrons, and electrons in each of these species.

O-18: 8 protons, 10 neutrons, 8 electrons F-18: 9 protons, 9 neutrons, 9 electrons

What is the number of protons, neutrons, and electrons for O-19, O-16, O-17, F-19, F-16, U-238, U-240?

O-19: 8 protons, 11 neutrons, 8 electrons O-16: 8 protons, 8 neutrons, 8 electrons O-17: 8 protons, 9 neutrons, 8 electrons F-19: 9 protons, 10 neutrons, 9 electrons F-16: 9 protons, 7 neutrons, 9 electrons U-238: 92 protons, 146 neutrons, 92 electrons U-240: 92 protons, 148 neutrons, 92 electrons

What does paramagnetic mean?

Paramagnetic means that a magnetic field will cause parallel spins in unpaired electrons and therefore cause an attraction.

What is the difference between the Lyman series, Balmer series, and Paschen series?

The Lymanseries has no visible wavlengths, and consists of electron transitions from energy levels n>/=2 to n=1. In other words, any electron that goes to 1. LArger energy transitions than the Balmer series, so shorter photon wavelengths in UV spectroscopy. -The Balmer consists of electron transitions from energy levels 3 or above to 2. In other words, any level 3 or higher then 3 down to 2 (n>/= 3 to n=2). of four wavelengeths in the visible region (pink is 410 nm, dark blue is 434 nm, light blue is 486 nm, and red/orange is 656 nm) -Paschen series is n>/= 4 to n=3.

When doing electorn configuration, where does the f block come before?

The f block fits between the s block and the d block between periods 4 and 5 in the periodic table.

In a neutral state, what is relationship between protons and electrons?

They are equal

What is an absorption spectrum?

To move electron to a higher energy state, it must absorb the exact amount of energy rewuired to reach that state. Each element has a distinct absorption spectrum, similar to the emission spectrum. They are equal (obviously).

Which electrons are the valence electrons of elemental vanadium, elemental selenium, and the sulfur atom in a sulfate ion?

Vanadium jas 5 valence electrons: two in 4s subshell and three in 3d subshell. -Selenium has six valence electrons: two in 4s and four in 4p. 3d is not part of valence shell because 4 is higher than 3. -Sulfur in a sulfate ion has 12 valence electrons: its original 6 plus 6 more from the oxygens to which it is bonded. Sulfur's 3s and 3p subshells can contain only 8 of these 12 electrons, so the other four electrons have entered sulfur stom's 3d subshell, which is normally empty in elemental sulfur.

What is an excited state?

WHen an electron "jumps up" to a higher orbital with a larger radius and higher energy, it is in an excited state. When electron moves to orbit of higher than normal energy.

What do we see in terms of obsorption?

We see the color of light that is NOT absorbed by compounds (how can we see it if the compounds absorbed it!) so we see the light that passes through.

Element Q consists of three different isotopes: A, B, and C. Isotope A has an atomic mass of 40 amu and accounts for 60% of naturally occurring Q. Isotope B has an atomic mass of 44 amu and accounts for 25% of naturally occurring Q. FInally, isotope C has an atomic mass of 41 amu and accounts for 15 % of Q. What is the atomic weight of Q?

-41.15 amu

What is the equation for electromagnetic energy of photons and where does it come from?

-As electrons jump from ground state to excited states, it's often very brief, and they return back to ground state quite rapidly. The energy they release as they return back to ground state is in the form of photons. -E = hc/wavelength. -h is planck's constant -C is speed of light (3.00 x 10^8 m/s)

What is the difference between atomic mass and atomic weight? What does atomic weight represent?

-Atomic MASS is nearly synonymous with MASS number. -Atomic WEIGHT is a WEIGHTED average of naturally occurring isotopes of that element. -A single atom as a set number of protons and neutrons.The atomic mass of an atom is EQUAL to the sum of protons and neutrons of an element - it is unequivical and wont change. -Atomic weight, on the other hand, is what we see in the periodic table and it is the weighted AVERAGE of the different isotopes of a single atom. -Atomic weight represents the mass of the avergae of the element and the mass of one molre of the element in grams.

Atoms generally exhist where? What would most likely change it?

-Atoms generally exhist in ground state (minimal energy). Extremely high temperatures or irradiation would most likely change it.

What did Bohr propose/assume? What equation did he come up with?

-Bohr assumed that the hydrogen atom had a central proton and that the electron traveled around the central proton in a circular orbit. The electrostatic force between the positively charged proton and the negtaively charged electron created the centripetal force causing the electron to orbit. -Bohr determined the angular momentum of an electron orbiting the hydrogen nucleus with the equation L = nh/2pi. n is the principal quantum number, 4 is PLanck's constant, and we all know what pi is.

What is difference between Bohrs model and quantum model?.

-Bohr said that electrons follow a clear defined pathway or orbital at a fixed distance from the nucleus. -Modern quantum mechanics say that electrons move rapidly and are localized WITHIN REGIONS of space around the nucleus called orbitals.

What are the exceptions to electron configuartion using Hund's rule?

-Chromium (and other elements in it's group) and copper (and other elements in it's group) are the exceptions. -For example, according to regular configuartion, chromium should have [Ar] 4s23d4. BUT if you move one electron from the s orbital to the d orbital, ALL of the subshell is half-filled (each electron gets their own seat) so the actual configuration is [Ar] 4s13d5. -These exceptions NEVER exist with p subshells.

What happens to difference in energy between two shells as distance from nucleus increases?

-Distance from nucleus increases, difference in energy between two shells decreases

What is Bohr's energy of electron equation?

-E = -Rh/n^2 Rh is the Rydberg unit of energy = 2.18 x 10^-18 J/electron. -MAIN CONCEPT from both equations is energy of electron changes slightly based on the quantum number.

What are electrons and where are they found? What is each charge equal to? What is mass?

-ELectrons move through space surrounding the nucleus, so they are on the outside of the nucleus. -Each electron has a charge equal to that of a proton with opposite sign, so each electron is -1. -Mass of electron is super tiny (1/2000 that of a proton), so negligible contribution to atomic mass.

What is a line spectrum? What is an atomic emission spectrum?

-Each line on the emission spectrum corresponds to a specific electron transition. -Each element has electrons that can be excited to a different set of distinct energy levels, so each element has an atomic emission spectrum - which is the distinct energy levels for that atom.

What are valence electrons? Why are they more likely to be involved in bonds?

-Electrons that are furthest away from the nucleus so they have strongest attractions with surrounding environment but weakest interactions within the nucleus -More likely to be involved in bonds because they experience the least electrostatic pull from their own nucleus.

What is absorption spectra used to identify?

-Elements in the gas phase.

What is the main trend in both equations?

-Energy of electron changes with respect to quantum number (n). -As n increases, the energy of an electron increases (it becomes less negative) and is farther away from the nucleus.

How do you write the electron configuration of an ion (an atom that is not neutral)?

-If it is an anion, you use the same rules and go up if you need to until all orbitals are filled. -Remember s is max 2, d is max 10, p is max 6, and f is max 14. -If it is a cation, you: A) Start with the neutral atom B) Remove electrons from subshells with highest n value. C) If n value are the same, the remove electrons from highest L values.

What theory did Max Planck develop and what is the equation?

-Max Planck developed the first quantum theory, proposing that energy emitted as electromagnetic radition comes from bundles called quanta. -The energy of quantum is E = hf -h is Planck's constant and is equal to 6.626 x 10^-34 J/s. -f is the frequence of radiation.

What is the charge on neutrons?Where are they found? What is mass?

-Neutrons are neutral, so they have no charge. -Mass of neutron is slightly larger than proton, but almost equal. -Found in nucleus.

What are protons and where are they found? What is each charge equal to? What is the mass?

-Protons are found in the nucleus of an atom. -Each charge of a proton is written as +1, aka e= 1.6 x 10^-9 C. -Mass of a proton is equal to 1 atomic mass unit, aka 1 amu.

Determine the spectroscopic notation on periodic table.

-S-block is columns 1 and 2 -D block is columns 3 to 12 -P-block is columns 13 to 18 (exception of helium. ) -F block is lanthanoids and actinoids.

What does Heisenberg's uncertainty principle state?

-States that it is impossible to simultaneously determine, with perfect accuracy, the exact momentum and position of an electron. -If we want to assess position, electron has to stop, and if we want to assess momentum, electron has to move, so we can never be sure of the exacts of those two qualities of an electron.

What is the equation for the energy of a photon and what does it state?

-States that the energy of the emitted photon corresponds to the difference in energy between the higher-energy initial state and the lower-energy final state. E=hc/wavelength = -Rh [1/ni^2 - 1/nf^2]

What are isotopes?

Atoms that have the same atomic number but different mass numbers.

Which subatomic particle is the most important for determining each of the following properties of an atom? - Charge, atomic number, isotope

Charge: Electrons because protons ALWAYS stay the same. Atomic number: Protons Isotope: Neutrons

How do energy levels differ between electrons close to vs far from nucleus?

Electrons close to nucleus have lower energy levels, electrons further away have higher energy levels.

What is Augbau's principle (AKA the building up principle)?

Electrons fill from lower to higher energy subshells. Each subshell will fill completely before electrons go to next one.

What is the electron configuration of Fe3+?

Fe3+: 4s23d3

How do valence electrons correspond to group number on periodic table?

Group 1: 1 valence electron Group 2: 2 valence electrons Groups 3 to 12: 3 to 12 valence electrons Group 13: 3 Group 14: 4 Group 15: 5 Group 16: 6 Group 17: 7 Grop 18: 8

What does half-life help determine?

Half-life determines an atom's stability, and longer-lasting isotopes are more abundant. Because of this, half-life determines relative proportions of different isotopes.

What did Bohr's model fail to explain?

How atoms behaved with more than one electron because he didn't take into account the repulsion between electrons.

Calculate the energy of a photon of wavelength 662 nm. (h-6.626 x 10^-34 J).

3.00 x 10^-28 J

Which will fill first, 5d or 6s?

6s

What is the difference between a continuous spectrum and a line spectrum?

A continuous spectrum is like a rainbow- how colors all blend with eachother continuously. -A line spectrum is observed with hydrogen. If you passed a current through a tube of hydrogen gas, the elcectrons in hydrogen atom will absorb energy and jump up to a higher energy level. When those electrons fall down to a lower energy level, they emit light (photons). The light would appear linear, 4 distinct/seperate lines of color.

WHat is a mole? What is it equal to.

A mole is a number of things (it could be atoms, ions, molecules), basically amount of substance equal to Avogadros number which is 6.02 x 10^23.

How did Bohr come to describe the structure of the hydrogen atom?

A nucleus with one proton forming a dense core, around which a sungle electron revolved in a defined pathway (orbit) at a discrete energy value ( like steps).

What does a positive and negative E correspond to?

A positive E corresponds to Emission, and a negative E corresponds to absorption.

The valence electron in a lithium atom jumps from the energy level n=2 to n=4. WHat is the energy of this transition in joules? in eV? (Note: Rh = 2.18 x 10^-18 J/electron = 13.6 ev/electron).

A) - 4.0875 x 10^-19 J/electron B) - 2.55 eV/electron

If an electron emits 3eV of energy, what is the corresponding wavelength of the emitted photon? (note 1eV = 1.60 x 10^-19 J, h = 6.626 x 10^-34)

A) 4.14125 x 10^-7 = 414nm

If given the following quantum numbers, which element (s) do they likely refer to? (Note: Assume that these quantum numbers describe the valence electrons in that element): A) n=2 and l=1 B) n=3 and l= 0 C) n=5 and l=3 D) n=4 and l=2

A) refers to any element with 2p, so possible elements are Boron, Carbon, Oxygen, Nitrogen, Fluorine, Neon?? B) refers to any element with 3s, so possible elements are sodium and magnesium. C) refers to any elements with 5f, so all the actinides. D) refers to 4d, so Y through Cd.

What are the four quantum numbers and what does each say? What does the Pauli exclusion principle state? Azimuthal quantum number: state, importance, range of values, letters that correspond to numbers, number of electrons, as value increases, energy does what? Magnetic quantum number: Importance, number of electrons, range of values? SPin quantum number: possible values, paired vs parallel?

-The four quantum numbers are n, l, ml, ms. -n: Principle quantum number: maximum number of electrons within a shell = 2n^2, so the further away an electron is from nucleus, the higher the orbital, the more electrons in that shell. -l: Azimuthal (angular momentum) quantum number. State: Important for bond angles and chemical bonding. Importance: Shape and number of subshells within a given principal energy level. Range of values: 0 to (n-1). Letters to numbers: When l=0, S. When l=1, P. When l=2, D. When l=3, F. Maximum number of electrons: 4l + 2 Energy increases as l increases. -ml: Magnetic quantum number. Importance: particular orbital within a given subshell that an electron is most likely to be found in at a given moment in time. Maximum number of electrons: 2 Range of values: intergers between -l and +l including 0. -ms: SPin quantum number. Possible values: -1/2 nd +1/2 Paired electrons: electrons with opposite spins (whenever two electrons are in same orbital, they must have opposite spins). Parallel electrons: electrons in different orbitals with the same spin. Pauli exclusion prinsiple says that no two electrons can have the exact same set of four quantum numbers.

What is the ground state of an atom? How does an electron move out of ground state?

-The ground state is the state of lowest energy, when all electrons are in lowest possible orbitals, and n=1. -If electron was given a buzz = energy exactly equal to amount of energy required to jump from one orbit to the next - the electron could jump out of the ground state and go to the next state.

Where is the mass number (A) found in periodic table and what does it represent?

-The mass number (A) of an element is the number found under each element on the periodic table. -It represents the sum of the protons and neutrons in an atom's nucleus.

What is the atomic number (Z) of an element equal to? Where is it found on periodic table?

-The number of protons found in the atom of that element. -Number on top of each element is that element's atomic number

What happens to electrons as they go from a lower energy level to a higher energy level?

-They get AHED. -A: Absorb light -H: Higher potential -E: Excited -D: Distant (from the nucleus).

What is the n + l rule? What happens if two subshells have the same value?

-Used to rank subshells by increasing energy. The lower the sum of the values of the first and second quantum numbers, the lower the energy of the subshell. The lowest one comes first. -If two subshells have the same value, the subshell with the lower n value has a lower energy and will fill with electrons first.

What does Hund's rule state?

-Within a given subshell, orbitals are filled so that there are a maximum of half-filled orbitals with parallel spins. (Like finding a seat on a crowded bus - you prefer to have your own seat than to share one). -Half-filled and fully filled orbitals have lower energies (higher stability).