ELECTRON AFFINITY, in chemistry, the amount of energy released when anelectron is added to a neutral atom to form a negatively charged ion. Since it is difficult to measure the it as an atom, the value is only available for a small number of chemical elements, mainly halogens. For ionization energies, there are two rules that govern the periodic trend of electrons affinity. 1 Electron affinity is less likely to be negative under the group. 2 As the principal quantum number increases, the size of the orbital increases and the affinities for electron' s decreases. Electronegativity is defined as a chemical property that determines the ability of an atom to attract an electron. In 1932 Linus Pauling proposed the concept of electronegativity. Electronaffinity is defined as the amount of ENERGY released when a molecule or neutral atom receives an electronS from the outside. The first of that is usually a negative value. When an ELECTRONS attaches to a neutral atom, ENERGY is released during the exothermic process. The second is the energies required to add the second  to the anion. Accepting Electron' s Easier Based on this code rule, this indicates that the higher the electronaffinity, the easier it is for an atom to accept. The low  indicates that the atom is difficult to accept .It increases from left to right within a certain period of time. This is due to the decrease in atomic radius. It decreases from top to bottom within the group. This is due to the increase in atomic radius. The noble gas element has a fully filled outer shell. Such electron configurations are very stable and, as such a noble gas, it is difficult to accept electron's. Therefore, the electron affinity of rare gas elements is zero. It Trends As the name implies, and is the ability of an atom to accept . Unlike electronegativity,  is a quantitative measure of the change in energy that occurs when an ELECTRON is added to a neutral gas atom. The negative the  value, the higher the affinityof the atom for electrons. The amount of energyreleased when electronsbind to a neutral atom to form an anion is called that. It is difficult to measure . It increases from left to right over a period of time due to the gravitational pull of the nucleus. As are added continuously away from the nucleus, the decrease  of the group should decrease. There are fewer electron bonds and it can be easily removed At some point, moving from left to right reduces the size of the atom due to increased nuclearenergy and thus increasedelectron acquisition enthalpy. However, going down the group in the periodic table increases the size of the atoms and reduces the electron gain enthalpy.