Oxidation States Flashcards
1
Q
what are oxidation states?
A
- these are numbers which are assigned to each element in a molecule or an ion by following a set of rules, they help us to see what is being oxidised or reduced.
2
Q
what is always the oxidation state for atoms in uncombined elements?
A
it is always 0
3
Q
what does the oxidation state always add up to in neutral molecules?
A
it always adds up to 0
4
Q
what does the oxidation sate always add up to in ions
A
always adds up to the overall charge on the ion
5
Q
What is the O.S of hydrogen?
A
+1
6
Q
The O.S of oxygen in all compounds
A
-2
7
Q
How to work out what has been oxidised and reduced?
A
- write out the equation and give the O.S of every element
- ignore the coefficients (big numbers)
- link up atoms of the same type
- look at the change in O.S
If the number has become more negative: reduction
If the number has become more positive: oxidation
If the number has not changed: redox reaction not occurred
8
Q
What is disproportionation?
A
When one particular element is simultaneously oxidised and reduced.
9
Q
Oxidation numbers in names of compounds
A
E.g in Iron (II) hydroxide, iron’s O.S would be +2 since it has the Roman numerals of 2.
The systematic name corresponds to the O.S
