Question

p type semi conductor is formed when trace amount of impurity is added to silicon. The number of valence electrons in the impurity atom must be:

• A. $3$
• B. $5$
• C. $1$
• D. $2$

Answer 1

The correct option is A $3$

To form a p-type semiconductor, one must add elements from boron family to the silicon atom.

Boron family has 3 valance electrons so, number of valance electrons in the impurity atom must be 3.