# What is the difference between electron affinity and ionization energy?

May 12, 2018

Well, the former is a reductive process...and ionization is an oxidative process.....

#### Explanation:

The electron affinity is the enthalpy associated with the formation of mole of gaseous anions, from one mole of gaseous atoms, and one mole of electrons:

$M \left(g\right) + {e}^{-} \rightarrow {M}^{-} \left(g\right) + \Delta$

And ionization enthalpy is the enthalpy associated with the formation of one mole of gaseous cations, and one mole of electrons from one mole of gaseous atoms....

$M \left(g\right) + \Delta \rightarrow {M}^{+} \left(g\right) + {e}^{-}$

Data on these processes inform our view of energy levels and electronic structure....

Electron affinities reasonably (why) INCREASE across a Period, from left to right as we face the Table, and decrease down a Group.

Ionization enthalpies ALSO increase across the Period, and decrease down the Group.