electron affinity

[Amanda Nguyen dis 2E]

How do you arrange B, Cl, and Ne according to electron affinity based on the most energy released by gaining an electron?



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[katrinahuwang_1L]

The more valence electrons an element has, the more likely it is to gain electrons so that a complete octet can be formed --> achieving a stable atom. The element that is most likely to gain an electron will release the most energy (so this is like the group 7 elements (halogens)). The addition of an electron to a neutral atom that is already stable isn't ideal, so energy would be absorbed when an electron is gained (this is like what happens with noble gases).

For your question, Cl would release the most energy because it is so close to getting a full octet and has the most valence electrons (7). The one that would release the second-most energy would be B. It has 3 valence electrons. The one that would absorb energy would be Neon since it's a noble gas and it doesn't really need any more electrons.

[Rachel Fox - 3F]

Ne will not have an electron affinity because it already has a full valence shell (which makes it stable), so it will not want to accept another electron. It would require the absorption of energy for Ne to accept an electron. Between Cl and B, Cl would release more energy than B because Cl only needs one more electron to fill its valence shell, so it has a higher electron affinity than B.