Redox

Question 1

Oxidation

Answer 1

When a species loses one or more electrons (there is an increase in oxidation number)

Question 2

Reduction

Answer 2

When a species gains one or more electrons (there is a decrease in oxidation number)

Question 3

Oxidation number

Answer 3

The charge that the element would have if the compound were fully ionic

Question 4

Disproportionation

Answer 4

A redox reaction in which an element in a single species is simultaneously oxidised and reduced

Question 5

Redox

Answer 5

When oxidation and reduction take place

Question 6

How to determine which atom has a negative OS in a molecule?

Answer 6

More electronegative species has the negative value. Electronegativity increases across a period and down a group

Question 7

What is hydrogen’s usual OS and the exceptions?

Answer 7

Usually +1, except for 0 in H and H2, and -1 in H- in sodium hydride NaH

Question 8

What is oxygen’s usual OS and the exceptions?

Answer 8

Usually -2, except 0 in O or O2, -1 in hydrogen peroxide, H2O2, and +2 in F2O

Question 9

What is fluorine’s usual OS and the exceptions?

Answer 9

Usually -1, except 0 in F and F2

Question 10

Reduction in OS means

Answer 10

Species has been reduced

Question 11

Increase in OS means

Answer 11

Species has been oxidised