Electron Affinity

[xenamclean_1G]

Can anyone explain what electron affinity is and more specifically, how it pertains to trends in the periodic table?

[kim 2I]

Electron affinity of an element is the energy released when an electron is added to a gas-phase atom. In terms of the periodic table, the highest electron affinities can be found toward the right side of the periodic table (especially the upper right near oxygen, sulfur, and the halogens).

[selatran1h]

Electron affinity is the energy released when an electron is added to the gas phase of an atom. It increases up a group and across a period from left to right. The elements with the highest electron affinities are located in the top right corner of the periodic table in group 17.

[Sydney Myers 4I]

It is important to note also that electron affinity can be a negative value. This occurs when it requires energy in order to add an electron to an atom. This happens with noble gases, for example.

[Jamie Lee 1F]

In high school, I learned to think of electron affinity as the "love an atom or molecule has for an electron". Usually, elements with electron shells that are almost filled tend to have greater electron affinities, or, they want to fill their shells more readily than other elements. For example, Fluorine would have a higher Eea than say Oxygen or Nitrogen because it has seven electrons in its shell and wants a full octet.

[Khushboo_3D]

He also defined electron affinity in class as the difference between the energy of the neutral atom and energy of the cation.

[805394719]

Electron affinity is the desire of an atom to receive an electron or the energy that is released when an electron is added to an atom. It increases from left to right and bottom to top, same as ionization energy, because the atomic radius decreases which increases the electrostatic interactions of the nucleus with an electron, making it easier to accept and electron and release more energy when it does. Different from the ionization energy, noble gases are not included in this trend since it is unfavorable to accept another electron to a valence shell that is already filled and stable.