Question

An atom has 2K,8L,5M electrons. Which of the following is its correct electronic configuration?

• A. $1s^{2}2s^{2}2p^{6}3s^{2}3p^2$
• B. $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$
• C. $1s^{2}2s^{2}2p^{6}3s^{2}3p^4$
• D. None of these

Answer 1

The correct option is B $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$

electronic configuration 2,8,5 $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$

Subshells 5 $(1s,2s,2p,3s,3p)$

Orbitals $9(1s,2s,2px,2py,2pz,3s,3px3py,3pz)$

Unpaired electrons $3(3px,3py,3pz)$

Number of electrons having$(l=1)=9(2p^6,3p^3)$