Question

Ionisation potential of elements on moving down a group:

• A. increases
• B. decreases
• C. constant
• D. none of these

Answer 1

Answer: (B)

decreases

The ionization energy, or ionization potential, is the energy required to completely remove an electron from a gaseous atom or ion. The closer and more tightly bound an electron is to the nucleus, the more difficult it will be to remove, and the higher its ionization energy will be. Ionization energy decreases moving down a group (increasing atomic radius). Group I elements have low ionization energies because the loss of an electron forms a stable octet.