Electron Affinity

[Megan Potter 1G]

what is electron affinity? like for the question: Which has a higher electron affinity - Chlorine (Cl) or Neon (Ne)?

[Patience Olsen 1A]

Electron affinity is the amount of energy released when an electron is added to a neutral atom. It can also be understood as the likelihood of an atom to accept an electron, so the halogens have the greatest electron affinity of all elements. Noble gases, being in a stable state, have the lowest electron affinity of all elements. By definition, chlorine has a higher electron affinity than neon.

[joannehaddad]

The trend for electron affinity is that it increases across a period and decreases down a group, so when answering questions phrased like that, you could just use the trend! Also, electron affinity is how many energy is spent or released when a neutral atom gets an electron added to it.

[Tarek Abushamma]

These trends have many of exceptions, however, so it is also important to take the element's electron configuration into consideration when determining how it would respond to additional electrons.

[Olivia Young 1A]

Electron affinity is the energy that is released when an electron is added to a gas-phase atom. Generally, the trend for electron affinity is that it increases left to right across a period until it reaches the noble gases and decreases going down a group. Of course there are exceptions to this trend, like the elements sulfur and oxygen. To answer your question, Chlorine has a higher electron affinity than Neon because Neon is a noble gas and it would therefore require energy to add an electron, versus the high amount of energy that would be released from adding an electron to Chlorine to achieve the most stable state under the octet rule.