Question

Choose the incorrect statement regarding ionization energy.

• A. Ionization energy increases along a period.
• B. Ionization energy is the amount of energy required to remove a single electron from a single atom.
• C. Ionization energy increases down a group.
• D. The sodium atom has lower ionization energy than chlorine atom.

Answer 1

The correct option is C Ionization energy increases down a group.

Ionization energy is the energy required to remove the outermost electron from the free and isolated atom of an element. Ionization energy increases along a period and decreases down a group. Sodium is a metal and has only one electron in its valence shell which can be easily removed. While chlorine has 7 electrons in the valence shell. It would rather gain an electron than losing.