JEE MAIN - Chemistry (2024 - 6th April Evening Shift - No. 13)
Evaluate the following statements related to group 14 elements for their correctness.
(A) Covalent radius decreases down the group from $$\mathrm{C}$$ to $$\mathrm{Pb}$$ in a regular manner.
(B) Electronegativity decreases from $$\mathrm{C}$$ to $$\mathrm{Pb}$$ down the group gradually.
(C) Maximum covalance of $$\mathrm{C}$$ is 4 whereas other elements can expand their covalance due to presence of d orbitals.
(D) Heavier elements do not form $$\mathrm{p} \pi-\mathrm{p} \pi$$ bonds.
(E) Carbon can exhibit negative oxidation states.
Choose the correct answer from the options given below :
Explanation
(A) Covalent radius of group 14 elements increases from $$\mathrm{C}$$ to $$\mathrm{Pb}$$.
(B) Electronegativity decreases from $$\mathrm{C}$$ to $$\mathrm{Si}$$ and thereafter it remains more or less constant.
(C) Maximum covalency of $$\mathrm{C}$$ is 4 as the outermost shell of $$\mathrm{C}$$ is $$2^{\text {nd }}$$ shell and it cannot expand its octet. But other elements can expand their covalency due to the availability of vacant d-orbitals.
(D) Heavier elements do not form $$\mathrm{p} \pi-\mathrm{p} \pi$$ bonds due to their larger atomic size.
(E) Carbon can show negative oxidation states when it is covalently bonded to less electronegative elements like $$\mathrm{CH}_4$$.
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