Question

4d, 5p, 5f, and 6p orbitals are arranged in order of decreasing energy. The correct option is:

• A. 5f > 6p > 5p > 4d
• B. 6p > 5f > 5p > 4d
• C. 6p > 5f > 4d > 5p
• D. 5f > 6p > 4d > 5p

Answer 1

The correct option is A

5f > 6p > 5p > 4d

The sequence in which various subshells are filled up can also be determined with the help of the (n + I )value for a given subshell.
The subshell with the lowest (n + I ) value is filled up first. When two or more subshells have the same (n + I) value, the. subshell with the lowest value of 'n' is filled up first.

Subshell	Value of ‘n’	Value of ‘l’	Value of (n+l)
4d	4	2	6
5p	5	1	6
5f	5	3	8
6p	6	1	7

As per (n+l) Value: 5f > 6p > 5p > 4d is the arrangement of given subshell in the order of decreasing energy.

Hence, Option (A) is correct.