Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Electron Affinity
Name:   Angela T.
Status:  student
Age:  16
Location: N/A
Country: N/A
Date: 2000

Why is the electron affinity of the 2a family members such as Be are so highly endothermic or positive?

Electron affinity is a measure of the attraction an element has for an electron. Those elements that have a high attraction for electrons, to form a closed shell in the case of the halides have a more negative (i.e. exothermic) energy. They "want" to attract an electron. Metals on the other hand, especially those in group I and II have very little propensity to gain an electron and form an anion. To the contrary they readily LOSE electrons to form cations.

Hence, their endothermic electron affinity.

Vince Calder

Click here to return to the Chemistry Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory