An element ' $M$ ' with electronic configuration $(2,8,2)$ combines separately with $(\mathrm{NO}_3)^{-}$, $(\mathrm{SO}_4)^{2-}$ and $(\mathrm{PO}_4)^{3-}$ radicals. Write the formula of the three compounds so formed. To which group and period of the Modern Periodic Table does the elements ' $''$ ' belong? Will ' $M$ ' form covalent or ionic compounds ? Give reason to justify your answer.