Question

State the electronic configuration for Potassium [$p=19,n=20$].

• A. $2,8,8,1$
• B. $2,8,8,2$
• C. $2,8,8,3$
• D. $2,8,8,4$

Answer 1

The correct option is A $2,8,8,1$

As we know, atomic no. is the total no of proton present in nucleus of an atom and atomic mass no is the total no of proton and neutron. So, potassium have atomic no. $19$ and mass no. $19+20=39$. K shell will accommodate $2$ electrons and L shell can accommodate $8$ electrons.$8$ electrons will be accommodated in M shell. The remaining $1$ electron will be accommodated in N shell.Hence, the electronic configuration will be $2,8,8,2.$