Topic 3 - Redox I Flashcards
What does an atom’s oxidation number tell you?
How many electrons an atom has donated or accepted to form an ion or form part of a compound.
What is an atom’s oxidation number the same as?
Its charge.
How does an atom’s oxidation number relate to a molecular ion’s overall charge?
The charge is equal to the sum of the oxidation numbers.
Describe the oxidation number of hydrogen.
- Usually -> +1
- In metal hydrides -> -1
- In molecular hydrogen -> 0
Describe the oxidation number of oxygen.
- Usually -> -2
- In peroxides (O₂²⁻) -> -1
- In molecular oxygen -> 0
How can the oxidation number of an atom or group be indicated in a formula?
Using Roman numerals.
How does the position of a Roman numeral in a formula relate to the oxidation numbers of the atoms or groups?
The Roman numeral is always after the thing it describes.
What is oxidation?
A loss of electrons.
What is oxidation?
Loss of electrons
What is reduction?
Gain of electrons
What is a redox reaction?
Where oxidation and reduction happen simultaneously.
What happens to the oxidation number when an electron is lost?
Increases by 1
What happens to the oxidation number when an electron is gained?
Decreases by 1
How can you work out if something has been oxidised or reduced?
- Assign oxidation numbers to the element before and after the reaction
- If the oxidation number increases -> This is oxidation
- If the oxidation number decreases -> This is reduction
What is a disproportionation reaction?
When a single species is simultaneously oxidised and reduced.