`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

Options

A. In case of C the valance 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

Answer

C

Explanation

The 4 bonding electron of C, Si and Ge lie, respectively, in the second, third and fourth orbit. Hence, energy required to take out an electron from there atoms (i.e. ionisation energy `E_(g)`) will be least for Ge, followed by Si and highest of C.