Question

Which of the following orbitals has the lowest energy?

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

Answer 1

Answer: (B)

$4f$

The energy of the orbitals are calculated using $n+l$ values of orbitals.

$4d=4+2=6$

$4f=4+3=7$

$5s=5+0=5$

$5p=5+1=6$

So $5s$ lowest energy.

Hence, option C is correct.