Question

Number of electrons in the valence shell of a semiconductor is
(A) $ 1 $
(B) $ 2 $
(C) $ 3 $
(D) $ 4 $

Answer 1

Hint: To answer this question, we need to consider the examples of the semiconductor elements. Silicon and Germanium are the common examples of the semiconductors. By considering the electronic configuration of these elements, we will get the required answer.

Complete step-by-step solution
We know that the most commonly used semiconducting elements include Silicon and Germanium. For obtaining the number of electrons in the valence shell of the semiconductors, we need to consider the electronic configuration of these elements.
We know that the atomic number of Silicon is equal to $ 14 $ . So the electronic configuration of silicon can be written as
 $ 1{s^2}2{s^2}2{p^6}3{s^2}3{p^2} $
Since the last electron gets filled in the third shell of Silicon, so the valence electrons are present in this shell. As we can see through the electronic configuration of Silicon, there are two electrons in the $ 3s $ orbital, and there are two electrons in the $ 3p $ orbital. So there are a total of four electrons in the valence shell of Silicon.
Now, we consider the case of Germanium. We know that the atomic number of Germanium is equal to $ 32 $ . So the electronic configuration of Germanium can be written as
 $ 1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}4{s^2}3{d^{10}}4{p^2} $
Since the last electron gets filled in the third shell of Germanium, so the valence electrons are present in the fourth shell. In the electronic configuration we can see that there are two electrons in each of the $ 4s $ and $ 4p $ orbital, thus accounting for a total of $ 4 $ electrons in the valence shell of Germanium.
Thus, the number of electrons in the valence shell of a semiconductor is equal to $ 4 $ .
Hence, the correct answer is option D.

Note
Semiconductors are widely used in daily application. They are used in the manufacturing of important devices such as transistors, ICs etc. These are used in designing the digital devices, which act as automatically controlled machines.