REDOX Flashcards
REDOX
- Both reactions happen at the same time
Reduction
-Group 1
-Group 2
-Group 3
Oxidation
-Group 5
-Group 6
-Group 7
Oxidation Number
Per Atom
What charge your element/compound has before undergoing oxidation
Assigning Oxidation Number
- Oxidation number of an ion = its charge
↳ e.g Bromine ion (Br^-1) is -1
↳ All group 7 elements have -1 charge - Oxidation number of H is +1
↳ Except when bonded to a Group 1 element where it is -1 - Oxidation number of oxygen is -2
↳ Except peroxides such as H2O2 where it is -1 - Oxidation number of an uncombined compound is 0
↳ e.g Nitrogen gas (N2) is 0 - For any neutral compound the sum of oxidation numbers of the atoms in the compound must equal 0
- For a polyatomic (compound has a charge), the sum of the oxidation numbers must be equal to its charge
Roman Numerals tell you the oxidation number
- (I) = 1
- (II) = 2
- (III) = 3
Positive: used for s-block & d-block metals
Ending ‘ate’
Examples: (Sulfate/Nitrate)
Contains oxygen
Ending ‘ide’
Examples: (Hydroxide)
Bonded w G5,G6,G7
Using Oxidation Number to write chemical formulae
- Put charge on individual atoms based on charges they form
Polyatomic ions & their charges
OILRIG
- Oxidation is LOSS of electrons
- Reduction is GAIN of electrons
-Substance that is reduced = OXIDISING AGENT
-Substance that is oxidised = REDUCING AGENT
Disproportion
An element is oxidised & reduced simultaneously
- Always look at the halogen (Group 7)
Basic
Half Equations
- Ionic half equations show oxidation or reduction
- Electrons are lost/gained shown in half equations
- Half equations (reduction & oxidation) can be combined to form full equation
Example
Magnesium burns Oxygen to form Magnesium oxide
Advanced
Half Equations
Use electrons(e-) hydrogen(H+) & water(H2O) to balance half equations
Acified manganate (VIII) ions (MnO4) can be reduced to Mn^2+ by Fe^2+ ions. Write the full redox equation for this reaction.
