8. Write down all the four quantum numbers for 19^th electron of Cr.

The atomic number of Cr is 24. It's electronic configuration can be written as:

1s² 2s²2p⁶ 3s²3p⁶ 4s¹ 3d⁵ (According to aufbau's principle 4s will be filled first and then 3d will be filled)

The 19^th electron of Cr will reside in 4s orbital. The quantum numbers can be given as:

n=4

l=0 (s)

m=0

s=+1/2 (upward spin)