5.1-5.3 Redox reactions and Oxidation and reduction

Reduction

________ is a reaction in which an element, ion or compound gains electrons.

Copper ions

________ have been reduced as the oxidation state has decreased from +2 in Cu2+ to 0 in Cu and they have gained electrons:

Aluminium

________ in a compound usually has the oxidation state +3.

II

Iron can form ions with a 2+ charge, called iron (________) ions or a 3+ charge, called iron (III) ions.

Roman numeral

The ________ is the oxidation state of the element.

Transition elements

________ can bond in different ways by forming ions with different charges.

CuO

The ________ is reduced to Cu by gaining electrons and has oxidised the hydrogen, so the oxidising agent is therefore copper oxide.

Oxidation

________ is a reaction in which an element, ion or compound loses electrons.

process of reduction

The ________ is very important in the chemical industry as a means of extracting metals from their ores.

iron

When ________ reacts with oxygen to form ________ oxide, the formula depends on the oxidation state of the ________ ions.

Reduction

________ is gain of electrons, loss of oxygen.

Oxidation

________ is the loss of electrons, gain of oxygen.

Oxidation and reduction in terms of electron transfer can be remembered by the mnemonic 'OIL RIG'

Oxidation Is Loss of electrons, Reduction Is Gain of electrons

Example redox equation

electron loss/gain and oxidation state