FC7: Ionisation Energies and Radii

Question 1

Atomic radius definition

Answer 1

The distance between the centre of the nucleus and the outer electron cloud.

Question 2

Nuclear charge definition

Answer 2

The positive charge on the nucleus given by the number of protons

Question 3

Shielding definition

Answer 3

When outer electrons are repelled by electrons in inner shells

Question 4

What is the atomic radius pattern across the period?

Answer 4

Decrease due to increased nuclesr charge due to increased protons

• additional electrons in same outer shell
• attraction of nucleus for outer electrons increases and pulls in outer shell

Question 5

Atomic radius down the group

Answer 5

Increase in atomic radius due to:-
Increased number of shells
Outweighing of the higher nuclear charge
Increased shielding due to increased inner electron shells

Question 6

What is ionisation energy measured in?

Answer 6

kJmol^-1

Question 7

What is the correlation between ionisation energy and atomic radius?

Answer 7

Greater atomic radius = lower ionisation energy as electrons are further from nucleus so it is easier to pull them away

Question 8

Definition of First ionisation energy

Answer 8

The energy needed to remove 1 mole of electrons from 1 mole of gaseous atoms.

Question 9

How do blips occur across a period at group 3 and group 6?

Answer 9

At group 3, the extra electron goes into a P orbital.
At group 6, electrons begin to pair up in the P orbital so less energy is required to release an electron as there is repulsion.