Test 1

Question 1

Atomic number

Answer 1

Number of protons, represented by ‘Z’,

Question 2

Atomic mass number

Answer 2

Number of protons and neutrons, represented by ‘A’

Question 3

Relative atomic mass

Answer 3

Atomic mass of an element relative to that of C-12

Question 4

Atomic mass unit

Answer 4

1 amu = 1.660 x 10^-27 kg

Mass of C = 12 amu
Mass of proton = mass of neutron = 1 amu

Question 5

Calculating relative atomic mass

Answer 5

If isotope A is x%, and isotope B is y%, do a weighted average of the relative atomic masses for each respective isotope

Question 6

Emission spectra of hydrogen gas

Answer 6

In the Balmer equation with nl and nh:

• Lyman series (UV region), l = 1
• Balmer series (Visible region), l = 2
• Paschen series (IR Region), l = 3

Question 7

Heisenberg uncertainty principle

Answer 7

It is impossible to accurately know both the position and the momentum of a particle at any given point in time

Question 8

PΨ

Answer 8

Potential portion of the Schrödinger equation, accounted for by the force of electrostatic attraction

Question 9

EΨ

Answer 9

Kinetic portion of the Schrödinger equation, shown by:

[(-h^2)/(8(Π^2)m)] operating on the partial derivatives of x, y, and z

Question 10

Particle in a one-dimensional box

Answer 10

Ψ = A sin(rx) + B cos(sx)

• To solve, take second derivative and multiply both sides by the Kinetic Hamiltonian operator and set x equal to n*pi to find s^2
• To find r^2, set x = 0 to get r = npi/a. Take what the kinetic portion of the hamiltonian equals, and expand the double derivative out to get [-h^2 thing](r^2)*[-A sin(rx)], substitute in the quantity for r^2, and Asin(rx) becomes Ψ. Then solve for r^2

Question 11

Radial function plots

Answer 11

• S-orbitals have finite value at nucleus, all other orbitals start at 0
• For the first orbital of any type, R(r) is always positive
• For the second orbital of any type, the radial function has only one sign change
• The points where the wavefunction changes sign represents the nodes

Question 12

Probability density plots

Answer 12

• All orbitals have zero probability at the nucleus
• Always positive
• Number of nodes is the same as in the corresponding wave function radial plot

Question 13

Nodes

Answer 13

Total number of nodes is n-1
Total number of angular nodes is l
Total number of radial nodes is n-1-l

Question 14

Pauli exclusion principle

Answer 14

Each electron must be described by a unique set of quantum numbers

Question 15

Hund’s Rule

Answer 15

Electrons should multiply the orbitals to have a maximum total spin, or maximum number of unpaired electrons

Question 16

Filling shells

Answer 16

Electrons are filled according to the lowest n+l values. If the n+l values are identical, the lower one is filled first

Question 17

Effective nuclear charge

Answer 17

Z* = Z - S = effective nuclear charge
S = shielding constant

Question 18

Shielding constant

Answer 18

• For ns and np electrons, electrons in same group contribute 0.35 (except 1s, which contributes 0.30), electrons in n-1 group contribute 0.85, and electrons in n-2 group contribute 1.00
• For nf and nd electrons, same group contributes 0.35, any other group contributes 1.00

Question 19

Expanded octet rule

Answer 19

Third period and onwards, as elements also have 3d orbital to utilize

Question 20

Lewis acids and bases

Answer 20

Molecules deficient in electrons or rich in electrons, respectively, acting as electron acceptors or donors

Question 21

VSEPR

Answer 21

Valence Shell Electron Pair Repulsion theory
m+n = 2: linear
m+n = 3: triangular 
m+n = 4: tetrahedral
m+n = 5: trigonal bipyramidal
m+n = 6: octahedral

Lone pairs occupy equatorial positions