Multiple choice

How does ionisation energy change as we go down a group in the modern periodic table?

  1. Increases

  2. Decreases

  3. No change

  4. First increases and then decreases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ionisation energy goes on decreasing down a group. It is due to increase in the distance between the valence electrons and the nucleus. As the atomic size increases down a group, the force of attraction between the nucleus and the valence electrons decreases. Therefore, the energy required to remove the electrons, i.e. ionisation energy, goes on decreasing.

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