This Challenge shows a catalytic process, and especially gives practice on electron-counting in transition metal complexes. Inorganic Challenges are exercises designed to be solved by a small group of students. Some Challenges practice a problem-solving algorithm, some reinforce important concepts, and some involve creativity or games. You can pick and choose Challenges from our Web site to increase active learning in your classroom, and we ask that you contribute creative Challenges of your own to give a head start to teachers at other colleges and universities!Please visithttp://chem.rochester.edu/~plhgrp/iicf/subjects.htm
(1) Students should be able to determine the total electron count of complexes and the oxidation state of the central metal ion. (2) Students should generalize the exception to the "18-electron rule" for square-planar d8 metal complexes. (3) Students should understand the terms "oxidative addition" and "reductive elimination." (4) Students should recognize the cyclic nature of a catalytic process.
This is designed to be assigned to small groups of 3-4 students, who work through the steps of the Inorganic Challenge.
No formal assessment of the benefits of this exercise has been conducted. The benefits of this exercise could be ascertained by asking a related question on a subsequent exam.
Qualitative monitoring of the students during the exercise indicates that students do not internalize electron counting and oxidation state calculation after lectures only. Common errors include: (a) counting neutral ligands as anionic, (b) forgetting to account for overall charge on the complex in oxidation state assignment, (c) mixing ionic and neutral electron-counting schemes. These problems can be corrected as part of group discussion. Because this catalytic cycle has complexes with different oxidation states, ligand types, and coordination numbers, they encounter a range of situations for identification of misconceptions.
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