Redox

• Chemistry
• Further Education (Key Stage 5)

Redox

Redox

An atom becomes an ion when it loses or gains an electron(s).

Redox fact

The term redox refers to the transfer of electrons during chemical reactions.

Redox fact

Oxidation is when atoms of an element lose electrons

Redox fact

Mg -> Mg2+ + 2e-  this is a half equation.

Redox fact

A half equation is an equation that shows the loss or gain of an electron(s) during a chemical reaction.

Redox fact

When electron(s) are gained this is reduction. 

Redox fact

Oxidation and reduction can occur at the same time due to the process of electron transfer.

Redox fact

Ionic compound forming is easy to write half equations for. This is not the case for covalent compounds. This is where we use oxidation states.

Redox fact

The oxidation state of atoms in a molecule of their pure element is always zero.

Redox fact

The sum of oxidation states in a molecule or compound is always zero.

What is oxidation?

1. A process that reduces the oxidation state of an atom.
2. A chemical reaction that involves the loss of electrons.
3. A chemical reaction that involves the gain of electrons.
4. A reaction that occurs in the absence of oxygen.

What is the process of oxidation?

1. Loss of electrons from a substance
2. Gain of protons by a substance
3. Increase in atomic mass of a substance
4. Reduction in the oxidation state of a substance

Which of the following is an example of oxidation?

1. Rusting of iron
2. Boiling water
3. Burning wood
4. Melting ice

What is the opposite process of oxidation?

1. Condensation
2. Reduction
3. Sublimation
4. Evaporation

What happens to the oxidation state of an element during oxidation?

1. It becomes negative
2. It increases
3. It decreases
4. It stays the same

What is the process in which one substance is reduced while another is oxidized?

1. Redox reaction
2. Neutralization reaction
3. Decomposition reaction
4. Combustion reaction

Which element is typically oxidized in a redox reaction involving a metal and a nonmetal?

1. Oxygen
2. Nonmetal
3. Hydrogen
4. Metal

0

What is the oxidation number of oxygen in most compounds?

1. -2
2. +2
3. 0
4. -1

What is the oxidation number of hydrogen in most compounds?

1. +1
2. -1
3. +2
4. 0

What is the oxidation number of an element in its pure form?

1. +1
2. 2
3. 0
4. -1

What is the oxidation number of alkali metals in compounds?

1. +2
2. -1
3. 0
4. +1

What is the oxidation number of halogens in compounds?

1. 0
2. +1
3. -1
4. -2

Describe oxidation, oxidation states/ oxidation numbers.

Explain which element is oxidised and which element is reduced in the previous slide's reaction.