Lecture 5

Question 1

size and energy

Answer 1

size of an orbital (H-atom) depends on energy

• the further the electron and nucleus are, the higher the energy is

Question 2

effective nuclear charge (Zeff)

Answer 2

actual nuclear charge experienced by electron, which is affected by how much nuclear charge is screened (shielded) by other electrons

Question 3

Zeff equation

Answer 3

Zeff = Z (actual nuclear charge) - S (shielding effect by other electrons)

Question 4

pairing energy

Answer 4

spins that are paired in an orbital experiencing repulsion

Question 5

atomic number

Answer 5

of protons

Question 6

atomic mass

Answer 6

of protons + neutrons

Question 7

energy of orbitals in H-atom vs multi-electron atoms

Answer 7

energy of multi-electron atoms are not only dependant on principle quantum number and they must pass through a region of electron density associated with core shell

Question 8

2s and 2p orbitals of lithium atom

Answer 8

• both orbitals are shielded by inner core (1s2) electrons but in different amounts
• inner lobe of electron density for 2s penetrates the 1s shell more, therefore electrons in 2s orbital are more shielded (higher effective nuclear charge)

Question 9

electron configuration

Answer 9

of electrons in each orbital in the lowest energy state

Question 10

rules for assigning electrons in orbitals

Answer 10

1. do not pair electrons until all orbitals are 1/2 full

2. maximize the spin (to make electrons interchangeable)