Question

An element 'X' belongs to fourth period and fifteenth group of the Periodic Table. Which one of the following is true ?

• A. Partially filled 'd' orbitals and completely filled 's' orbitals.
• B. Completely filled 's' orbitals and completely filled 'p' orbitals
• C. Completely filled 's' orbitals and half-filled 'p' orbitals
• D. Half-filled 'd' orbitals and dompletely filled 's' orbitals

Answer 1

Answer: (C)

Completely filled 's' orbitals and half-filled 'p' orbitals

Answer 2

Since the element 'X' belongs to fourth period and fifteenth group of Periodic Table, its outer electronic configuration is $4s^2 \, 4p^3$
Its complete electronic configuration is $1s^2, \, 2s^2, \, 2p^6, \, 3s^2 \, 3p^6, \, 4s^2, \, 2d^{ 10}, \, 4p^3$Hence, its s. orbital is completely filled while p-orbital is half-filled.