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Posted: Fri Dec 07, 2018 9:07 pm
how do we find oxidation number? is it something we have to memorize? (like how do. you know the oxidation number of CN is -1?)
Posted: Fri Dec 07, 2018 9:13 pm
For CN (Cyanide) yes you must memorize the charge of -1. There is a list on Professor Lavelles website titled "Naming Coordination Compounds" that has all the ligands you need to memorize along with their charges. If its not on there, its either a transition metal that can have multiple oxidation states or its charge can be found by simply counting which group the element is in.
Posted: Fri Dec 07, 2018 9:16 pm
I think it's helpful to just memorize the oxidation states of the molecules that we've been practicing during the lectures because they'll most likely pop up during the exam at some point and it'll be helpful if you know it right away. But if you don't, you can always try doing the Lewis structure. For cyanide, the carbon has a triple bond with nitrogen, so the carbon has a lone pair which gives it a negative charge of 1.
Posted: Fri Dec 07, 2018 10:01 pm
There are some common ligands that you should familiarize yourself with the charges. But as for finding the oxidation state of transition metals, it is based on the overall charge of the coordination compound. For example: Ag(CN)2- has an oxidation state of +1 because CN has a charge of -1 and there is 2 of them. The overall charge of the compound is -1 so therefore the charge of silver must be +1
Posted: Fri Dec 07, 2018 10:10 pm
For cyano- we need to know it's -1, and for the charge on metal ion we could basically calculate it.
Posted: Sun Dec 09, 2018 3:12 am
ah i see; i suppose i will just memorize them. thank you!