Electron affinity reflects
the ability of an atom to accept an electron. It is the energy change that
occurs when an electron is added to a gaseous atom.
- These reactions tend to be exothermic (release energy) because an electron approaching a neutral atom experiences an attraction for the positively charged nucleus.
- So the values of EA are generally negative. The higher (more negative) the EA, the more easily it accepts an electron.
- The smaller the atom, the closer an added electron can approach the atomic nucleus and the more strongly it is attracted to the nucleus.
- However, affinity does not always release energy. In some cases affinity requires energy.