(i).Element K (potassium) has 1 electron in the outermost shell.
(ii)Element Be (beryllium) and Ca (calcium) belong to same group because both of them are in the second group because their outermost shell has 2 electrons that is their valency is 2. So we keep them in same group.
(iii)Element Fe (iron) and K (potassium) belong to same period that is period 4.
K (potassium) has a greater atomic size because K is at left side of the period and Fe is at right side as compared to K. So as we go from left to right in period, the size of atom decreases as the no. of valence electrons increase.