Question

If in nature there may not be an element for which the principal quantum number n > 4, then the total possible number of elements will be.

• A. 60
• B. 32
• C. 4
• D. 64

Answer 1

Answer: (A)

60

Answer 2

For n=1, maximum number of states $= 2n^{2} = 2$and for n = 2, 3, 4, maximum number of states would be 8, 18, 32 respectively, Hence number of possible elements

= 2 + 8 + 18 + 32 = 60.