For an element such as sodium, how many ionization energies are there?

Sodium has 496KJ/mol ionization energy.

Explanation:

Ionization energy is the process in which electron which is present in the outermost shell is removed with the absorption of energy by the electron. Different atoms have different ionization energies. When we go from left to the right in the periodic table, ionization energy increases due to atomic size decrease. When we go from top to bottom in the periodic table, ionization energies decreases due to increase the atomic size. Sodium has 496KJ/mol ionization energy which means the outermost electron needs 496KJ/mol energy for removal.