An element's second ionization energy is the energy required to remove the outermost, or least bound, electron from a 1+ ion of the element. Because positive charge binds electrons more strongly, the second ionization energy of an element is always higher than the first.

What is second ionization energy with example?

The first ionization energy of sodium, for example, is the energy it takes to remove one electron from a neutral atom. The second ionization energy is the energy it takes to remove another electron to form an Na²⁺ ion in the gas phase.

What is meant by 1st and 2nd ionization energy?

First ionization energy: The energy needed to remove the outermost, or highest energy, electron from a neutral atom in the gas phase. Second ionization energy: The energy it takes to remove an electron from a 1+ ion (meaning the atom has already lost one electron and now removing the second).