Question

An element 'X' belongs to fourth period and fifteenth group of the periodic table. Which one of the following is true regarding the outer electronic configuration of 'X' ?

• A. It has partially filled d-orbitals and completely filled s-orbitals.
• B. It has completely filled s-orbitals and completely filled p-orbitals.
• C. It has completely filled s-orbitals and half-filled p-orbitals.
• D. It has half-filled d-orbitals and completely filled s-orbitals.

Answer 1

The correct option is C It has completely filled s-orbitals and half-filled p-orbitals.

The electronic configuration of X can be written as$X=1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^3$So, element 'X' has completely filled s- and d-orbitals and half- filled p-orbitals.

Note: Since, element 'X' belongs to fourth period, $n=4$. For fifteenth group, general outer electronic configuration is $n{s}^{2}n{p}^3$.