chemistry as level topic 3 redox

Question	Answer
what are the main rules from oxidation numbers	single elements = 0 pairs of identical atoms = 0 monoatomic ion = same as it's charge molecular ions = sum of all is the charge hydrogen = 1+ oxygen + 2- group 6 and 7 = 6+ and 7+ group 1 and 2 = 1+ and 2+
how do you know if something has been oxidised	there is a loss of electrons, so increased oxidation number
how do you kno0w if something has been reduced	there had been a gain of electrons, so lower oxidation number
what is a disproportionation reaction	one element is simultaneously oxidised and reduced
what is a half equation	it shows the electrons that are being lost/gained. combining two half equations gives the full equation.
how to write a half equation	separate the elements. write an equation for each, balancing out the elements, adding water/oxygen if needed, and then adding electrons to balance out the charges. now balance the 2 equations so there are the same number of electrons. then add the 2 equations together.
how to write a normal redox equation	write the oxidation number of everything under the equation. add numbers to beginning of elements to balance out the oxidation numbers of the elements. add water/hydrogen if needed.

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	Created by Talya Hambling almost 9 years ago

	Copied by Imogen Hockenhull almost 8 years ago