1.1 Formulae & Equations

Question 1

Oxidation number

Answer 1

The number of electrons that an atom uses to bond (electrons added/subtracted from an element to make it neutral)

Question 2

OIL RIG

Answer 2

Oxidisation is loss of electrons, reduction is gain.

Question 3

The oxidation number of an unconmbined element

Answer 3

0

Question 4

All oxidation numbers in a compound must add to

Answer 4

0

Question 5

All oxidation numbers in an ion must sum to

Answer 5

The overall charge

Question 6

Oxidation numbers of group 1 metals

Answer 6

+1

Question 7

Oxidation number of group 2 metals

Answer 7

+2

Question 8

Oxidation number of combined oxygen

Answer 8

-2

Question 9

Oxidation number of combined hydrogen

Answer 9

+1

Question 10

What are oxidation numbers useful for?

Answer 10

Redox reactions (reduction and oxidation take place) to show which species is oxidised and which is reduced. Oxidation number increase = oxidised. Oxidation number decrease = reduced.

Question 11

What is a spectator ion?

Answer 11

Ions in a reaction that do not determine the outcome or observation.

Question 12

What is a half equation/ionic equation?

Answer 12

An equation showing the part of the reaction that creates an observation.