Question

If aufbau rule in not followed, the ${19}^{th}$ electron of Sc(Z=21) will have

• A. n=3,l=0
• B. n=3,l=1
• C. n=3, l=2
• D. n=4,l=0

Answer 1

The correct option is D n=4,l=0

$Sc(Z=21)=[Ar{]}^{18}4s^{2}3d^1$ ,${19}^{th}$ electron enters into 4s orbital. For 4s orbital n=4 and l=0