Question

What is the electronic configuration of lithium [ Atomic no. = 3, Mass no. = 7]?

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

Answer 1

The correct option is D $2,1$

The atomic number of lithium is $3$. K shell will accommodate $2$ electrons and L shell will accommodate the remaining $1$ electron.Hence, the electronic configuration will be $2,1.$