Arrange the following elements in decreasing order of their energy ga…

The correct answer is Option (3) → (B), (D), (A), (C)

The energy gap \( E_{g} \) between the valence and conduction bands decreases down group 14, from an insulator (diamond) through semiconductors (Si, Ge) to a metal-like element (Sn).

    \( \text{(B) Carbon (Diamond): } E_{g} \approx 5.4\,\mathrm{eV} \)

    \( \text{(D) Silicon: } E_{g} \approx 1.1\,\mathrm{eV} \)

    \( \text{(A) Germanium: } E_{g} \approx 0.7\,\mathrm{eV} \)

    \( \text{(C) Tin: } E_{g} \approx 0 \ \text{(the bands overlap or nearly touch)} \)

Decreasing order: (B), (D), (A), (C).

NCERT (2026-27):
Extrinsic Semiconductor – “… Though the above description is grossly approximate and hypothetical, it helps in understanding the difference between metals, insulators and semiconductors (extrinsic and intrinsic) in a simple manner. The difference in the resistivity of C, Si and Ge depends upon the energy gap between their conduction and valence bands. For C (diamond), Si and Ge, the energy gaps are 5.4 eV, 1.1 eV and 0.7 eV, respectively. Sn also is a group IV element but it is a metal because the energy gap in its case is 0 eV.”