Ionisation energies

Why do elements in a group have similar properties?

Similar outer electron configuration

Periodicity

Repeating pattern across different periods

First Ionisation energy

Energy needed to remove an electron from each atom in 1 mole of gaseous atoms

Factors affecting ionisation energy

• Nuclear attraction, more protons

• Atomic radius, weaker attraction due to distance

• Shielding, weakening attraction due to outershell being repelled

Why are successive ionisation energies larger?

The ion formed is smaller and the proton:electron is greater, so the attraction between nucleus and electron is stronger

Why are there jumps in ionisation energy

Jumps between inner shells means a stronger attraction between electron and nucleus so more energy is required to overcome

Location of element based on successive ionisation energy

Big jump between two ionisation energies, element is in the group of the ionisation energy before the jump

Across a period

• nuclear charge increases

• shielding stays the same

• nuclear attraction increases

Down a group

• atomic radius increases

• shielding increases

• nuclear attraction decreases