Question

Which subshell is at a higher energy level in multi electron species 4f or 5d?

Answer 1

Energies of various sub-shell in a​ multi electron atom can be predicted with the help of​ ‘n + l’ rule.​

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For sub-shell 4f , the ‘n + l’ value = 4+3= 7
For sub-shell 5d , the ‘n + l’ value = 5+2= 7
For the same value of (n+l), the orbital with higher value for ’n’ is higher in energy.
Hence 5d sub-shell have more energy.