Larger the value of ionization enthalpy, more difficult will be the removal of electron to form cation.

Electron gain enthalpy is the measure of the ease with which an atom receives the additional electron in its valence shell in gaseous phase. So, larger is the value of electron gain enthalpy, easier is the formation of anion.

Electronegativity (Mulliken) = .

As Z eff increases, the valence shell as well as inner shells electrons are more strongly attracted by the nucleus. This causes the contraction in atomic size