IONISATION ENERGY Flashcards
what is ionisation energy
energy needed to remove one mole of electrons from one mole of gaseous atoms
trend of ionisation energy down group 2
1st ionisation energy decreases - more shielding because there are more shells between the nucleus and the elctron being removed so the electron being removed is further from the nucleus
trend of ionisation energy across period 3
1st ionisation energy increases - nuclear charge increases and similar shielding because all the electrons being removed are from the same shell
why is aluminium anomalous
aluminiums outer electron is in the 3p orbital which has slightly higher energy so less energy is needed to remove it
why is sulphur anomalous
in sulphur one of the 3p orbitals contain a pair of electrons and they repel eachother making the electron easier to move
