Oxidation and Reduction

Question 1

What is oxidation

Answer 1

When an element loses electrons, gains oxygen or loses hydrogen

Question 2

What is reduction

Answer 2

When an element gains electrons, loses oxygen or gains hydrogen

Question 3

What is an oxidising agent

Answer 3

A substance that brings about oxidation in other substances while it itself is being reduced

Question 4

What is a reducing agent

Answer 4

A substance that brings about reduction in other substances while it itself it being oxidised

Question 5

Define the oxidation number

Answer 5

The charge that an atom has or appears to have when electrons are distributed according to certain rules

Question 6

What are the 2unofficial rules when assigning oxidation numbers

Answer 6

1. Group 1 becomes +1

2. Group 2 becomes +2

Question 7

Name any 3 rules for assigning oxidation numbers and explain them

Answer 7

1. The ox.n of any uncombined element is 0
2. The ox.n of an ion of an element is the same as its charge
3. The sum of the ox.n of all the eleents in a compound must add up to 0
4. Oxygen always has an ox.n of -2, except in hydrogen peroxide (-1) and OF2 (+2)
5. Hydrogen is always assigned an ox.n of +1 except in metal hydrides (-1)
6. Halogens always have an ox.n of -1 unless bonded to a more electronegative atom
7. The sum of the ox.n of all the elements in a complex ion must equal the charge on the ion