Question

Why do noble gases have very high ionisation energies?

Answer 1

1. Noble gases have a very stable electronic configuration with completely filled outermost shells (closed-shell configuration).
2. Removing an electron from this stable configuration requires a large amount of energy.
3. Their atoms have a strong effective nuclear charge attracting the valence electrons tightly.
4. This makes it very difficult to remove an electron, resulting in very high ionisation energies.
5. Ionisation energy decreases down the group due to increasing atomic size and lower attraction on valence electrons.