C and Si both have same lattice structure, having 4 bonding

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

1. In case of C the valence band is not completely filled at absolute zero temperature.
2. In case of C the conduction band is partly filled even at absolute zero temperature.
3. 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.
4. The four bonding electrons in the case of C lie in the third orbit, whereas for Si they lie in the fourth orbit.

Correct Option: C

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