If the electronic configuration of an element is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s², the four electrons involved in chemical bond formation will be_____.
A. 3p⁶

B. 3p⁶, 4s²

C. 3p⁶, 3d²

D. 3d², 4s²

The outermost orbital is also known as valence orbital and the electrons present in that orbital participate in the bond formation.

For the given electronic-configuration the d and s orbitals are the outermost orbitals.

Thus, the 4 electrons involved in chemical bond formation will be

3d², 4s².