Question

Name the element having highest ionization energy in the periodic table ? Explain why

Answer 1

Helium is the element with the highest ionization energy.
It is a noble gas with a full octet and is stable. It requires a large amount of energy to remove an electron from helium atom.
The valence electrons in He are in K shell which lies very close to the nucleus of the atom. Therefore, it requires more energy to remove an electron
from K shell than any other shell.