Question

Which group contains elements which are hardest to ionize?

Answer 1

Answer:

Group 18

Explanation:

The ionization energy of the elements increases as one moves up a given group because the electrons are held in lower-energy orbitals, closer to the nucleus and therefore are more tightly bound (harder to remove).

Answer 2

Answer:

Group 18

As we move across the period, the no. of shells decrease.So the tendancy to attract electron is more which leads to the Higher attraction force between atom.Therefore elments are hardest to ionize because Ionisation is the energy required to remove an atom.