Using oxidation numbers in equations

https://www.youtube.com/watch?v=XH4b0RRqPGQ

How to work out which chemicals are oxidised and reduced in chemical reactions

First we must assign oxidation numbers

Mg and Cl2 have oxidation numbers of 0

Mg has oxidation num of +2, chlorine has oxidation num of -1

We always write oxidation number for ONE atom in reactions

We can see magnesium oxidation number increased from 0 to +2, so it has been oxidised.

Chlorine oxidation number decreased from 0 to -1, shows reduction has taken place.

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