the distance from centre of nucleus to last orbit.it is measured in angstron
the amount of energy required to remove the last electron from its valency shell.it is measured in electron volt.
the amount of energy required to release an electron in the valency shell of an atom.it is measured in electron volt
atomic radius decreases in a period while increases in a group
ionisation energy increases in a period while decreases in a group
electron affinity increases in a period while decreases in a group.