Electrons will first enter into which set of quantum numbers-n = 5, l = 0 or n = 3, l = 2

Options

A. n = 5, l = 0
B. Both possible
C. n = 3, l = 2
D. Data insufficient

Answer

C

Explanation

According to Aufbau.s principle, electron enters in the orbitals according to their energy. Energy of an orbital is proportional to the sum (n + l). If for two orbitals (n + l) is equal then electron will be filled in the orbital having lesser value of n.
Hence, here electron will be filled in the orbital with n = 3, l = 2.