Although La has a 6 s 25 d 1 valence electron configuration, the valence electron configuration of the next element-Ce-is 6 s 25 d 04 f 2. Further complications occur among the third-row transition metals, in which the 4 f, 5 d, and 6 s orbitals are extremely close in energy. For example, Nb and Tc, with atomic numbers 41 and 43, both have a half-filled 5 s subshell, with 5 s 14 d 4 and 5 s 14 d 6 valence electron configurations, respectively. In the second-row transition metals, electron–electron repulsions within the 4 d subshell cause additional irregularities in electron configurations that are not easily predicted. Table 23.1 Valence Electron Configurations of the First-Row Transition Metals Sc Because the ns and ( n − 1) d subshells in these elements are similar in energy, even relatively small effects are enough to produce apparently anomalous electron configurations. In Chapter 7 "The Periodic Table and Periodic Trends", we attributed these anomalies to the extra stability associated with half-filled subshells. Unexpectedly, however, chromium has a 4 s 13 d 5 electron configuration rather than the 4 s 23 d 4 configuration predicted by the aufbau principle, and copper is 4 s 13 d 10 rather than 4 s 23 d 9. With two important exceptions, the 3 d subshell is filled as expected based on the aufbau principle and Hund’s rule. As we go across the row from left to right, electrons are added to the 3 d subshell to neutralize the increase in the positive charge of the nucleus as the atomic number increases. The valence electron configurations of the first-row transition metals are given in Table 23.1 "Valence Electron Configurations of the First-Row Transition Metals". ![]() zip file containing this book to use offline, simply click here.Įlectronic Structure and Reactivity of the Transition Metals You can browse or download additional books there. More information is available on this project's attribution page.įor more information on the source of this book, or why it is available for free, please see the project's home page. Additionally, per the publisher's request, their name has been removed in some passages. However, the publisher has asked for the customary Creative Commons attribution to the original publisher, authors, title, and book URI to be removed. Normally, the author and publisher would be credited here. This content was accessible as of December 29, 2012, and it was downloaded then by Andy Schmitz in an effort to preserve the availability of this book. See the license for more details, but that basically means you can share this book as long as you credit the author (but see below), don't make money from it, and do make it available to everyone else under the same terms. ![]() This book is licensed under a Creative Commons by-nc-sa 3.0 license.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |