3: Redox I Flashcards
Use PPQs for spec points: 8-10, 13
Define oxidation number.
The number of electrons that an atom used to bond with atoms of another element.
What are the oxidation numbers of a combined oxygen?
-2
-1 in peroxides
+2 when bonded to fluorine
What are the oxidation numbers of a combined hydrogen?
+1
-1 in metal hydrides
Explain oxidation and reduction in terms of electron transfer and oxidation number.
Oxidation:
Loss of electrons
Oxidation number increases
Reduction:
Gain of electrons
Oxidation number decreases
What happens to oxidising and reducing agents interms of electron transfer?
Oxidising agent - gains electrons
Reducing agent - loses electrons
What is a disproportionation reaction?
An element in a single species is simultaneously oxidised and reduced.
How do metals generally form ions?
They form positive ions by loss of electrons with an increase in oxidation number.
How do non-metals generally form ions?
They form negative ions by gain of electrons with a decrease in oxidation number.
