Preiodicity

Question 1

Metallic character

Answer 1

The preference to lose electrons

Question 2

Atomic Radii definition

Answer 2

half the distance between two nuclei

Question 3

Ionic radii

Answer 3

The internuclear distance in ionic solids

Question 4

Ionisation energy

Answer 4

The energy change when an electron is removed from an atom of the element in gas phase

Question 5

Electron gain energy (aka electron affinity)

Answer 5

The energy change that occurs when an electron is attached to an atom in the gas phase

Question 6

Atomic radii trends

Answer 6

Left to right: Decrease in radii, increase in nuclear charge (more protons) , increased electrostatic interaction
Top to bottom: Increase in radii, distance of valence orbitals increases, valence electrons lie further away

Question 7

Ionic radii trends

Answer 7

Left to right: Decrease in radii, increase in nuclear charge, increased electrostatic interaction
Top to bottom: Increase in radii, distance of valence orbitals increases, valence electrons lie further away

Question 8

First IE trends

Answer 8

Left to right: Increase - increased nuclear charge increases electrostatic attraction
Top to bottom: Decrease - increasing valence electrons further away from nucleus

Anomalies: H->Be, Be->B, N->O

Question 9

Anomalies of IE

Answer 9

Be-> B
Full s orbital has added stability compared to 2s22p1
Ionisation of B = easier due to favourable 2s2 configuration

N-> O
Added stability with half-filled orbital
O - 2p4 = easier to ionise due to added stability
Stability due to electron spin of 4th electron

Question 10

Define the IE for an element. Explain why the IE of sodium is smaller than that of magnesium

Answer 10

Definition:
Energy change when one mole of an atom has an electron removed in the gaseous state.
Explanation:
Mg has one more proton than Na, so the effected nuclear charge (Zeff) is bigger. Higher nuclear charge increases the electrostatic interaction between the nucleus and the valence electrons, so more energy is required to remove an electron

Question 11

Electron gain energy trend

Answer 11

Left to right: Decreases - higher effective nuclear charge results in easier to gain electrons

Anomalies: Full or half orbitals are not good at accepting orbitals

Question 12

Which of the following pairs of elements has the higher first IE?
(a) Be or B
(b) C or Si
Justify your answers

Answer 12

(a) Be - has a higher ionisation energy, B - 2p1, thus, removing electron that is further away, plus added stability of full 2s orbital.
(b) C - electrostatic interaction between nucleus and valence electrons of C is stronger than Si due to fewer orbitals in the electronic structure.