RX + PT Flashcards
(88 cards)
Define oxidation (3)
- Addition of oxygen
- Loss of hydrogen
- Loss of electrons
Define reduction (3)
- Loss of oxygen
- Addition of hydrogen
- Gain of electrons
Define oxidation number
The oxidation state/charge of an element or ionic substance
Oxidation number of uncombined elements
0
Oxidation number of a monoatomic ion
The charge of the ion
Oxidation number of molecular ions
Sum of oxidation numbers is equal to overall charge
Oxidation number of a neutral compound
Overall charge is 0, sum of oxidation numbers is 0
Oxidation number of hydrogen
+1
Oxidation number of oxygen
-2
Oxidation number of halogens
-1
Oxidation number of group 1 metals
+1
Oxidation number of group 2 metals
+2
Oxidation number of oxygen in peroxides
-1
Oxidation number of hydrogen in metal hydrides (MHx)
-1
When are Roman numerals used?
For transition metals with variable oxidation numbers
Oxidation state of S block elements (Group 1 and 2)
- Lose electrons
- Oxidised
- Positive oxidation numbers
Oxidation state of P block elements
- Gain electrons
- Reduced
- Negative oxidation number
What is an oxidising agent?
- Gains electrons
- Reduced
- Increase in oxidation number
What is a reducing agent?
- Donates/loses electrons
- Oxidised
- Decrease in oxidation number
Define redox reaction
A reaction where reduction and oxidation occurs simultaneously
Define disproportionation reaction
A reaction in which an element in a single species is simultaneously oxidised and reduced
Trend in oxidation of metals
- Lose electrons
- Increase in oxidation number
- Oxidised
- Positive ions formed
Trend in oxidation of non metals
- Gain electrons
- Decrease in oxidation number
- Negative ions formed
Steps for ionic half equations and full ionic equations
- Write half equation for first element
- Balance all species excluding oxygen and hydrogen
- Balance oxygen by adding H20
- Balance hydrogen by adding H+ ions
- Balance charges using e- electrons
- Write half equation for second element
- Balance
- Ensure both equations have the same number of electrons
- Combine
- Cross off any common substances