Draw the dot and cross structure of the following:

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

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

$$\begin{aligned}\overset{\phantom{2}{2}}{\text{H}} \space {\swarrow}\mathllap{\searrow} \space \overset{2}{\text{Cl}} \Rightarrow \underset{\phantom{2}{2}}{\text{H}} \space {\swarrow}\mathllap{\searrow} \underset{\phantom{2}{2}}{\text{Cl}} \\[1em] \text{H}_2\text{Cl}_2 \Rightarrow \text{HCl}\end{aligned}$$

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