C and Si both have same lattice strcture, having 4 bonding electron in each. However, C is insulator whereas Si is intrinsic semiconductor. This is because:

Options

(a) In case of V the valence band is not completely filled at absolute zero temperature.
(b) In case of C the conduction band is partly filled even at absolute zero temperature.
(c) The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.
(d) The four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit.

Correct Answer:

The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.

Explanation:

Electronic configuration of ⁶C = 1s², 2s², 2p²
The electronic condiguration of ¹⁴Si = 1s², 2s², 2p⁶, 3s², 3p²
As they are away from nucleus, so effectg of nucleus is low for Si even for Sn and Pb are most mettalic.