(a) what is the electronic configuration of (i) a sodium atom, and (ii) and oxygen atom?
(b) what is the number of outermost electrons in (i) a sodium atom, and (ii) and oxygen atom?
(c) show the formation of `Na_(2)O` by the transfer of electrons between the combining atoms.
(d) why are ionic compounds usually hard?
(e) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state?