Explanation: Atoms in Group 2A have 2 valence electron and lose 2 electron to gain an octet. These cations have +2 charge. Transition Metal Cations Electrons are removed from ns subshell before the (n-1)d subshell Fe atom = [Ar]4s23d6 Fe2+ ion = [Ar]3d6 Fe3+ ion = [Ar]3d5 The 4s electrons have been removed.
