 The exceptions are the elements in the boron and oxygen family, which require slightly less energy than the general trend.The electron affinity of an atom can be described either as the energy released by an atom when an electron is added to it, conversely as the energy required to detach an electron from a singly charged anion.The sign of the electron affinity can be quite confusing, as atoms that become more stable with the addition of an electron (and so are considered to have a higher electron affinity) show a decrease in potential energy; i.e.