Question

If elements with principal quantum number n>4 were not allowed in nature, the number of possible elements would be

• A. 60
• B. 32
• C. 4
• D. 64

Answer 1

The correct option is A

60

The maximum number of electrons in an orbit are $2n^2$. If n>4 , is not allowed, then the number of maximum electrons that can be in first four orbit are:

$2(1{)}^2+2(2{)}^2+2(3{)}^2+2(4{)}^2=2+8+18+32=60$

Therefore, possible elements can be 60.