# Ionisation Energy vs First Ionisation Energy [closed]

It was stated in a textbook that the first ionisation energy is

the minimum energy needed to remove one mole of electrons from one mole of gaseous atoms in their ground state

Is there a difference between ionisation energy and first ionisation energy?

## closed as unclear what you're asking by Mithoron, Tyberius, M.A.R., andselisk♦, Todd MinehardtSep 13 '17 at 16:18

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• There is a first, second, third, fourth, … ionisation energy. Does that answer your question? – Jan Sep 13 '17 at 11:05
• @Jan not really. chemguide.co.uk/atoms/properties/moreies.html explains the successive ionisation energies with the equations, but ionisation energy isn't explained. – George Tian Sep 13 '17 at 11:17
• Well, ionisation energy is the general term and first ionisation energy specifies. As you would expect from language. – Jan Sep 13 '17 at 11:24
• en.wikipedia.org/wiki/Ionization_energy – Mithoron Sep 13 '17 at 14:09

• No. The definition of ionization energy is $\ce{X + \text{energy} -> X+ + e-}$, with nothing about atoms or moles. It's all about the units, which work out to be per mole. Units are consistent between all successive ionization energies. – pentavalentcarbon Sep 14 '17 at 12:27