Draw the dot and cross structure of the following:

(a) An ionic compound formed when Mg reacts with the dilute HCl.

(b) A covalent compound formed when H₂ reacts with Cl₂.

(c) The positive ion produced when ammonia gas is dissolved in water.
[Atomic number: Mg = 12, Cl = 17, H = 1, N = 7]

(a) When Mg reacts with the dilute HCl, MgCl₂ formed.

(b) Covalent compound formed when H₂ reacts with Cl₂ is HCl.

$\overset{\phantom{2}{2}}{\text{H}} \space {\swarrow}\mathllap{\searrow} \space \overset{2}{\text{Cl}} \Rightarrow \underset{\phantom{2}{2}}{\text{H}} \space {\swarrow}\mathllap{\searrow} \underset{\phantom{2}{2}}{\text{Cl}} \\[1em] \text{H}$2\text{Cl}2 \Rightarrow \text{HCl}

(c) The positive ion produced when ammonia gas is dissolved in water is ammonium ion.