A1.3 ionisation energy

what it about atoms that make it stable

when they have a full set of elections in their outer shell

which is why the noble gases are so unreactive

first ionisation energy

the minimum energy needed to remove an electron from a neutral atom

what happens to ionisation energies as we go from group 1 to group 0

they increase

why do group 1 metals have the smallest ionisation energies

they only have 1 election in their outer shell. if thy lose this then they have a full outer shell

why do noble gases have the biggest ionisation energies

noble gases have a full outer shell, they are very stable (balanced) as they are

why do ionisation energies increase from group 1 to group 0

the number of protons in the nucleus increase. there is more electrostatic attraction to the nucleus so more energy is needed to remove the electron

why does ionisation energy decrease from period 1 to period 5

• shells act as shielding from the attraction of the protons

• the electrons is further from the nucleus, so the attraction is weaker