Question

The atomic number of the element with highest ionization energy among the following is

• A. Z = 16
• B. Z = 14
• C. Z = 13
• D. Z = 15

Answer 1

Answer: (D)

Z = 15

Answer 2

For element with Z = 15, electronic configuration is $1s^2 2s^2 2p^6 3s^2 3p^1_x 3p^1_y 3p^1_z$ Due to exactly half filled configuration of $3p$ orbital, the element will have the highest ionization energy.