An element 'M' with electronic configuration 2 8 3 combines separately with Cl^-, SO₄^-2 anions. Write the chemical formulae of the compounds formed. Predict with the suitable reason the nature of the bond formed by element 'M' in general. How will the electrical conductivity of the compounds formed vary with respect to 'M'?

(i) Given, electronic configuration of M is 2, 8, 3. Hence, its valency is +3.

When M and Cl^- combine

Chemical formula of iron (III) sulphate:

$\text{M}^{3+} \space \text{Cl}^{1-} \\[1em] \overset{\phantom{22}{3}}{\text{M}} \space {\swarrow}\mathllap{\searrow} \space \overset{1}{\text{Cl}} \Rightarrow \underset{\phantom{2}{1}}{\text{M}} \space {\swarrow}\mathllap{\searrow} \underset{\phantom{2}{3}}{\text{Cl}} \\[1em] \text{MCl}_3$

∴ Chemical formula will be MCl₃

(ii) When M and SO₄^-2 combine

$\text{M}^{3+} \space \text{SO}$4^{2-} \\[1em] \overset{\phantom{22}{3}}{\text{M}} \space {\swarrow}\mathllap{\searrow} \space \overset{2}{\text{SO}4} \Rightarrow \underset{\phantom{2}{2}}{\text{M}} \space {\swarrow}\mathllap{\searrow} \underset{\phantom{2}{3}}{\text{SO}4} \\[1em] \text{M}2\text{(SO}4)3

∴ Chemical formula will be M₂(SO₄)₃

M in general forms Ionic bond because it acquires a stable electronic configuration of neon (2, 8) by losing its three valence electrons to form M³⁺ cation.

Compounds of M will be ionic compounds so they will conduct electricity in liquid or molten state only but not in solid state. Element 'M' on the other hand can conduct electricity in solid state due to the presence of 3 free electrons in its outermost shell.