7 oxidation, reduction and redox reactions Flashcards Preview

A Level Chemistry > 7 oxidation, reduction and redox reactions > Flashcards

Flashcards in 7 oxidation, reduction and redox reactions Deck (10):


a reaction in which an atom or group of atoms loses electrons (add oxygen / remove hydrogen)


oxidising agent

a reagent that oxidises (removes electrons from) another species - electron acceptors



a reaction in which an atoms or group of atoms gain electrons (remove oxygen / add hydrogen)


reducing agent

a reagent that reduces (adds electrons to) another species - electron donors


redox reactions

short for reduction-oxidation reaction, it describes reactions in which electrons are transferred from one species to another


half equation

an equation for a redox reaction which considers just one of the species involved and shows explicitly the electrons transferred to or from it


ionic equation

a chemical equation where the electrolytes in aqueous solution are written as dissociated ions, in a balanced ionic equation, the number and type of atoms are the same on both sides of the reaction arrow


oxidation states/number

the number of electrons lost/gained by an atom in a compound compared to the uncombined atom. it forms the basis of a way of keeping track of redox (electron transfer) reactions



describes a redox reaction in which the oxidation states of some atoms of a particular element increases and that of other atoms of the same element decreases


rules for oxidation states (4)

1. uncombined elements have o.s. of 0
2. some elements always have same o.s. except:
H - 1+ except metal hydrides (NaH), where it's 1-
Group 1 - 1+
Group 2 - 2+
Al - 3+ always
O - 2- except peroxides where 1-, and OF2 where 2+
F - 1- always
Cl - 1- except in compounds w F and O, where it's +ve
3. sum of all o.s. in comp = 0 since all comps electrically neutral
4. sum of o.s. in complex ion = charge of ion
5. the most electronegative element always has -ve o.s.