Periodic Trends and Properties

Question 1

Ionization energy

Answer 1

• amount of energy required to remove an electron from an atom or ion
• increases to right –> and up ^
• Helium needs largest energy cuz needs most to remove (full orbital)

Question 2

When looking at electronic configurations how do you determine the number of electrons?

Answer 2

count the superscripts for # of electrons and they would (usually) convert to the elemental symbols if charge is neutral

Question 3

Ionization energy is usually expressed in eV, joules, or kilojoules. Would it be difficult to remove electrons from group IA?

Answer 3

No, the first should have relatively low values of IE. The first electron will be removed easily.
2nd IE is hard because it will have configuration like noble gas. Therefore, higher IE for 2nd IE.

Question 4

Is the second ionization energy lower or higher than the first ionization energy?

Answer 4

2nd IE is always greater than 2nd IE. It is more difficult to remove an electron from a +ve charged species (once the first is removed, it becomes +ve)

Question 5

What is effective nuclear charge?

Answer 5

Zeff
- the net +ve charge of valence e- from nucleus
Zeff = Z (atomic number) - S (shielding electrons)

Question 6

What is the trend for Zeff?

Answer 6

• remains constant down a group (since valence e- constant) - but shielding occurs with more e- down the group
• increases towards the right with more +ve nucleus

Question 7

How is frequency involve with the energy of a photon?

Answer 7

Ephoton = hf

Question 8

What is plancks constant?

Answer 8

4.15x10-15

Question 9

For a Zinc ion what ion is it most likely to form with a 3d10valence structure?

Answer 9

Zn2+.

It will remove 2 electrons from the 4s shell and leave a full d shell.

Question 10

Diamagnetic vs paramagnetic

Answer 10

diamagnetic total spin = 0 ( in same orbital and cancel out)

paramagnetic (unpaired electron in any orbital)

Question 11

How to determine electron configurations with charges?

Answer 11

• don’t forget to remove #x of electrons associated with the charge

Question 12

True of False:

Two electrons with the same n, l, ms values can be in different orbitals of the same subshell.

Answer 12

True. I.e. 2 e- in the 2p subshell (pxpypz) with the same spin
ml is different (-1 (px) , 0 (py), +1(pz))

Question 13

What is the only thing that doesn’t increase as Zeff increases?

Answer 13

Atomic radius!

• as valence e- increase with a more +ve nucleus
• and radius decreases cuz attraction increases

Question 14

Which is higher, the first ionization energy or second ?

Answer 14

Second IE is always higher cause it is difficult to remove

Question 15

What has a higher IE, Nitrogen (5) or Oxygen (6)?

Answer 15

Nitrogen has it’s p orbital half filled
Oxy has one p orbital fully filled and two partial; therefore it is easier to remove that single e- to make all orbitals partially filled
Oxygen has a lower IE, Nitrogen has a higher IE

Question 16

Exceptions to electron configuration

Answer 16

Cr and Cu

• completely full or partial full d sublevel is more favourable
• an electron from 4s orbital is excited to the 3d orbital (3d5 or 3d10)

Question 17

What has a larger atomic radius? Cation or Anion?

Answer 17

anion has a larger atomic radius
cations are smaller than their corresponding element’s neutral atom cuz less e- to produce shield effect and less e- means less repulsion outwards and more attraction towards the nucleus

Question 18

In general, do metals have +ve or -ve oxidation states?

Answer 18

• positive oxidation states for metals