NEET2026ChemistryChapterActual
Which of the following statements regarding Group 14 elements and their allotropes is incorrect?
Options
- ACarbon cannot expand its coordination number beyond four due to the absence of d -orbitals in its valence shel
- BThe heavier elements of this group do not readily form p - p multiple bonds with themselves.
- CDiamond is the most thermodynamically stable allotrope of carbon at standard temperature and pressure.
- DThe relative stability of the +2 oxidation state increases down the group from Germanium to Lead.
Correct answer
C. Diamond is the most thermodynamically stable allotrope of carbon at standard temperature and pressure.
Step-by-step solution
Carbon cannot expand its coordination number beyond four because it lacks d -orbitals in its valence shell. This makes the first statement correct. Heavier elements of Group 14 (like Si, Ge, Sn, Pb) have larger atomic sizes, which results in diffuse p -orbitals. This prevents effective lateral overlap, so they do not readily form p - p multiple bonds with themselves. This makes the second statement correct. Graphite is the most thermodynamically stable allotrope of carbon at standard temperature and pressure, not d