[Unit 1.6] | Electron Arrangement & Ionisation Energy

Question 1

What is 1st Ionisation Energy?

Answer 1

The energy (kJ/mol) required to remove 1 mole of electrons from 1 mole of gaseous atoms.

Question 2

What is the equation for 3rd Ionisation Energy?

Answer 2

X²+(g) –> X³+(g) + e-

Question 3

What happens as you try to remove electrons from increasingly charged ions?

Answer 3

Ionisation energy becomes higher.

Question 4

What 3 factors decrease IE?

Answer 4

• Increased atomic radius: Electrons in the furthest shells experience less attraction the further they are from the nucleus.
• Decreased nuclear charge: With less protons, the electrons are less attracted to the nucleus.
• Increased Electron Shielding: Inner shells repel outer ones, meaning that having more shells decreases IE.

Question 5

Describe IE trends down a group.

Answer 5

• Radius & Shielding Increase greatly, causing a generally decreasing trend in energy.
• Nuclear charge has a negligible increase.

Question 6

Describe IE trends across a period.

Answer 6

Generally, the energy increases as the nuclear charge increases with minimal impact on shielding and radius.

Question 7

What does a large increase in IE suggest?

Answer 7

It suggests when an electron is removed from an orbital closer to the nucleus.