Statement I : Ionic size of O-2>F->Na+>Mg+2Statement II : In isoelectronic species, ionic size decreases with increase in effective nuclear charge

In isoelectronic series as negative charge decreases and positive charge increases,effective nuclear charge increases hence ionic size decreases.All the species contain same number of electrons but number of protons increases with increase in positive charge or decrease in negative charge;Effectively nucleus becomes more powerful, attraction increases, size of ion decreases