Which element has the highest energy level?

Which element has the highest energy level?

The first ionization energy varies in a predictable way across the periodic table. The ionization energy decreases from top to bottom in groups, and increases from left to right across a period. Thus, helium has the largest first ionization energy, while francium has one of the lowest.

How do you determine the highest energy level?

For most elements in their ground state, the period number in which they are located corresponds to the highest energy level that contains electrons.