Solved 2024 Sample Question Paper CBSE Class 10 Science — Question 2

(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.