|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
1997
>
January
> |
|
Information • Textbooks • Media • Resources
|
|
|
|
Electron Affinities of the Alkaline Earth Metals and the Sign Convention for Electron Affinity
|
John C. Wheeler
Department of Chemistry and Biochemistry, University of CaliforniaŠSan Diego, La Jolla, CA 92093-0340
|
|
January 1997
Vol. 74 No. 1
p. 123
|
|
|
|
| Abstract |
|
Most general chemistry textbooks published in the last six years contain tables or figures showing the alkaline earth metals with large endothermic electron affinities. These data come from outdated extrapolations and are seriously in error. It has been known since 1987, both theoretically and experimentally, that the ion Ca- is stable. It is now certain that Sr-, Ba-, and Ra- are also stable, and accurate values for the electron affinities of Ca-, Sr-, and Ba- have been determined. Recommended values for these electron affinities, in the units commonly employed in introductory texts and with the sign convention used here, are 2.37, 5.03, and 13.95 kJ/mol for Ca, Sr, and Ba, respectively. The endothermic electron affinities often quoted for Be and Mg are also too large and should be reported simply as ">0". An argument for a return to the original sign convention for the electron affinity is presented in this paper.
|
|
| More Information |
 Citation |
Wheeler, John C. J. Chem. Educ. 1997 74 123.
|
Keywords |
|
History |
Created:
Last Updated: |
July 29, 1999
June 23, 2005
|
|
|
|
|
|
| Home > JCE Print > Journal of Chemical Education > Issues >
1997
>
January
> Page
123
|
|
|
| Chemistry Teacher Connection |
|
The "Chemistry Teacher Connection" (CTC) is especially for high school chemistry teachers. For only $40/year, it offers an online-only subscription to CLIC along with membership in the Division of Chemical Education, normally $65/year. CTC subscribers receive access to all articles and supplements from 1996 through the current issue.
|
| C&EN CLICs |
|
Through special arrangement with the ACS, JCE High School CLIC is now able to provide subscribers with online access to Chemical & Engineering News articles that have been selected specifically for secondary science instructors and their students.
|
JCE Collections Available
|
Occasionally, collections of JCE back issues become available for donation to individual teachers, schools, or libraries. JCE matches collections with interested recipients. Recipients pay shipping costs or pick up the collection.
|
| Contributions Welcome |
| JCE welcomes your submission |
| Fishing for New Ideas |
 Always in the
process of
improving, CLIC
welcomes ideas and comments.
Email Us |
|
