1. B .......... it has less ioni. energy, less likely to form ion and react, therefore its a halogen under Cl on the periodic table, and has a wider radius due to more shells
2. B ...........ionic bond = cation + anion, Mg has charge 2+ and Cl has charge 1- forming MgCl2
also Mg is a metal and Cl is non metal
but H and Cl ions also bond to form hydrogenchloride. but both H and Cl are non-metals. so B is the best answer.
