Ionisation energy

Ionisation energy

Energy required to remove a mole of electron from a mole of atoms in gaseous state

How is ionisation energy represented

A(g) → A+(g) + e-

Why is energy required to remove an electron from an ion higher compared to a neutral atom

the attraction is much stronger as there are more protons and less electrons

Why are there big jumps in successive energies of an element

Evidence for quantum shells as removing an electron from a shell closer to the nucleus requires more energy

Why is removing electrons from a shell closer hard

Less shielding from other electrons

Increasing positive charge

Why does ionisation energy increase across a period

Due to the rise in number of protons

Why is ionisation energy lower in group 3

Elements have one electron in 3p1 which is further away from the nucleus and experiences more shielding

Why is ionisation energy lower in group 6

Elements have 4 electrons in 3p meaning two electrons are paired so they repel each other

Lower ionisation energy in group 3 and group 6 is evidence for what

Sub shells

What is the trend in ionisation energy down a group

Ionisation energy decreases as outer electron gets further away from the nucleus so experience more shielding