How many electrons a re there in the valence shell of (i) a magnesium atom, and (ii) an oxygen atom?

42 Name the anode and the cathode used in the electrolytic refining of impure copper metal. 43 Write the electron arrangement in (i) a magnesium atom, and (ii) an oxygen atom. 43 Show on a diagram the transfer of electrons between the atoms in the formation of MgO. 43 Name the solvent in which ionic compounds are generally soluble.