$(a)$ Show the formation of $MgO$ by the transfer of electrons.
$(b)$ Name the cation and anion.
$(c)$ Write three properties of ionic compounds.

(N/A) Formation of $MgO$:
$Mg (2, 8, 2) \to Mg^{2+} + 2e^-$
$O (2, 6) + 2e^- \to O^{2-}$
$Mg^{2+} + O^{2-} \to MgO$
$(b)$ $(i)$ Cation: Magnesium ion $(Mg^{2+})$.
$(ii)$ Anion: Oxide ion $(O^{2-})$.
$(c)$ Properties of ionic compounds:
$(i)$ They are generally crystalline solids and are soluble in water.
$(ii)$ They have high melting and boiling points due to strong electrostatic forces of attraction.
$(iii)$ They conduct electricity in the molten state or in aqueous solution because the ions are free to move.