Question

Arrangement of the following group of orbitals in which they fill with electrons :
(5f, 6p, 4p, 6s, 4d, 4f )

• A. $4p,4d,6s,4f,6p,5f$
• B. $6s,4d,4f,5f,4p,6p$
• C. $6s,4p,4d,4f,5f,6p$
• D. $4d,4p,4f,5f,6s,6p$

Answer 1

Answer: (A)

$4p,4d,6s,4f,6p,5f$

Electrons will first fill orbitals by the sum of the quantum numbers n and l. Orbitals with equal values of (n+l) will fill with the lower n values first.

So energies of $4p,4d,6s,4f,6p,5f$ are 5,6,6,7,7,8 respectively.
Hence option A is correct.