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 priciple, electron enter in the orbitals according to their energy. Energy of an orbital is proportional to the sun (n+l). If the 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