Alkali metals are strong reducing agents because after the removal of the only valence electron (ns1) they can gain the electronic configuration of noble gases (n−1)p6, that is more stable electronic configuration. KO2 is paramagnetic oxide due to the presence of 1 unpaired electrons. The number of electrons present is 17 where the sixteen electrons are from two oxygen atoms and one from the negative charge (O2−). Its molecular orbital configuration can be written as σ1s2σ×1s2σ2s2σ×2s2σ2pz2π2px2=π2py2π×2px2=π‌×2py1σ×2pz0. So, statement (B) is wrong. The hydration enthalpies of alkali metal ions decrease with increase in ionic sizes. Li+>Na+>K+>Rb+ Li+has maximum degree of hydration and for this reason, lithium salts are mostly hydrated, e.g. LiCl⋅2H2O.
