redox I Flashcards
what is the oxidation number of uncombined elements/diatomic molecules?
0
what is an oxidation number?
the number of electrons an atom has donated/accepted to form an ion
what is the oxidation number of a monatomic ion?
its charge e.g. Na+ has an oxidation number of +1
what is an oxidising agent?
accept electrons and become reduced
what is a reducing agent?
they donate electrons and become oxidised
what is oxidation?
loss of electrons, molecule becomes positive
what is reduction?
gain of electrons, molecule becomes negative
what is a disproportionation reaction?
when an element in a single species is simultaneously oxidised and reduced
what is the oxidation state of hydrogen?
+1 EXCEPT in metal hydrides where its -1
what is the oxidation state of oxygen?
-2 EXCEPT in peroxides where it is -1
what is the oxidation state of aluminium?
always +3
what is the oxidation state of fluorine?
always -1
what is the oxidation state of chlorine?
-1 EXCEPT if in a compound with oxygen or fluorine where it would be positive
what happens to the oxidation number if electrons are lost?
increases by 1 for every lost electron
what happens to the oxidation number if electrons are gained?
decreases by 1 for every gained electron