Question

The decreasing order of energy for the electrons represented by the following sets of quantum numbers is :
1. n = 4, l = 0, m = 0, s = $\pm$1/2
2 .n = 3, l = 1, m = 1, s = -1/2
3. n = 3, l = 2, m = 0, s = +1/2
4. n = 3, l = 0, m = 0, s = -1/2

• A. 1 > 2 > 3 > 4
• B. 2 > 1 > 3 > 4
• C. 3 > 1 > 2 > 4
• D. 4 > 3 > 2 > 1

Answer 1

Answer: (C)

3 > 1 > 2 > 4

Principle of (n +l) rule :
The subshell with the lowest ($n+l$) value has the lowest energy. When two or more subshell have the same ($n+l$) value then the subshell with the lowest value of n have lower energy.

So, the order of energy will be $3>1>2>4$.