Redox
reactions that include both reduction and oxidation
oxidation
the process of losing electrons and when the oxidation number increases
reduction
process of gaining electrons and when the oxidation number decreases
what does the oxidation number tell us
how many electrons are used when an element is bonded to other atoms in a compound
what’s the oxidation number of uncombined element
0
what’s the oxidation number of metals when combined in a compound
group 1- +1
group 2- +2
group 3- +3
what’s the oxidation number of fluorine
ALWAYS -1
what’s the oxidation number of hydrogen
mostly +1 but in metal hydrides e.g. NaH it’s -1
oxidation number of oxygen
mostly -2
in peroxides e.g h2o2 it’s -1
with fluorine it’s positive because fluorine is always -1
oxidation number of chlorine
mostly -2
in a neutral molecule what’s the sum of the oxidation numbers
zero
in compound ions what’s the sum of oxidation number
it’s the same as the charge on the ion
oxidising agent
it’s what’s reduced, it gains electrons and it oxidises another species
reducing agent
it’s what’s oxidised, it loses electrons and it reduces another species
what does the redox reaction of metals reacting with acids form?
a salt plus hydrogen
