Electronegativity is defined as the tendency of atoms to draw electron clouds of other atoms towards them. Atoms such as fluorine, chlorine, oxygen, nitrogen and phosphorous have greater tendencies to draw electrons towards themselves. Compared to these, atoms such as Li, Na, Mg, K and so on have a tendency to release electrons away from them and are electropositive. Quantitative scales of electronegativity can be set up and in the Pauling's scale of electronegativity, F has an electronegativity of 4 and Li has an electronegativity of 1. Electronegativities of a few atoms are given in Table 8.1. It is not easy to quantify electronegativity. The differences in the ionization potentials, electron affinities, binding energies and electronic configurations of atoms and so on, all contribute to electronegativity.