Question

Which element has the first highest ionization potential?

Answer 1

Heya friend!!
Rajdeep here....

Ionisation potential is the energy required to remove an electron from an isolated atom in its gaseous state.

As you move left to right across a period, the number of shells remain the same but number of Valence electrons increases by one, Due to which the nuclear pull on the valence electrons increases, so more energy is required to remove the valence electrons. Thus, Helium (He) is the element with highest ionization potential.

Thanks!!

Answer 2

Ionisation potential increases across a period and decreases down a group. Helium (He) is having highest first ionization potential(2370 KJ mol-1).