The energy given off when a neutral atom in the gas phase picks up an electron to form a negatively charged ion.
the energy change that occurs when an atom gains an electron
the ability of an atom to attract electrons to itself
The electron affinity is a measure of the attraction between the incoming electron and the nucleus. The higher the attraction, the higher the electron affinity. www.chemguide.co.uk/inorganic/group7/properties.html
The energy released when an electron is added to an atom.
The amount of energy absorbed in the process in which an electron is added to a neutral isolated gaseous atom to form a gaseous ion with a 1- charge; has a negative value if energy is released.
The electron affinity, Eea, of an atom or molecule is the energy required to detach an electron from a singly charged negative ion, that is the energy change for the process