Transcript Ionisation Energy

Ionisation
Energy
Ionisation Energy, Ei
• This is the amount of energy needed to
remove the outer electron from an atom.
• Actually from an isolated neutral atom in the
gaseous state.
Periodicity of Ei
• Minimum Ei – group 1A metals
• Maximum Ei – group 8A noble gases
• Increases across a period
• Decreases down a group
• periodicity is due to electron configuration
Ei increases
Ei decreases
Trends in ionisation energy
Periodic trends in Ei
Factors influencing Ionisation
Energy
• Atomic Radius - distance from the
nucleus
• Nuclear Charge - increases with the
number of protons in the nucleus
• Electron Shielding - outer shell
electrons are repelled by inner shell
electrons, so are shielded from the
nucleus’ positive charge
Ionisation Energy Factors
• Distance from
nucleus
• Electron
shielding
• Nuclear charge
Variation in Ei across a
period