3.1.7 Oxidation, Reduction, and Redox Reactions Knowledge Flashcards
what is oxidation in terms of transfer of electrons?
the loss of electrons
what happens to the oxidation state, when a species is oxidised?
increases - number becomes more positive
what is reduction in terms of transfer of electrons?
the gain of electrons
what happens to the oxidation state, when a species is reduced?
decreases - number becomes more negative
what is a redox reaction?
reaction where oxidation and reduction take place at the same time
what is a reducing agent in terms of transfer of electrons?
- electron donor
- a reducing agent is itself oxidised
what is an oxidising agent in terms of transfer of electrons?
- electron acceptor
- an oxidising agent is itself reduced
what are oxidation states used for?
to follow the movement of electrons in redox reactions; to identify which substances have been oxidised and reduced
is the charge or number given first in oxidation states?
charge
what oxidation state do uncombined elements have?
0
what is the sum of all oxidation states in a compound?
0
what is the oxidation state of a simple ion equal to?
its charge
what is the sum of all oxidation states in a complex ion equal to?
its charge
what is the oxidation state(s) of hydrogen?
- usually +1
- in metal hydrides (e.g. LiH) -1
what is the oxidation state(s) of group 1 metals?
+1
what is the oxidation state(s) of group 2 metals?
+2
what is the oxidation state(s) of aluminium?
+3
what is the oxidation state(s) of oxygen?
- usually -2
- in peroxides (e.g. Na2O2), -1
- when reacted with fluorine (OF2), +2
what is the oxidation state(s) of fluorine?
-1
what is the oxidation state(s) of chlorine?
- usually -1
- is positive if reacted with oxygen or fluorine
what is the oxidation state(s) of bromine?
- usually -1
- is positive if reacted with oxygen or fluorine
what is the oxidation state(s) of iodine?
- usually -1
- is positive if reacted with oxygen or fluorine
why is the oxidation state of fluorine always -1?
it is the most electronegative element; no other element can remove an electron from fluorine
in what order are oxidation states assigned?
- Uncombined elements (0)
- Metals (G1, G2, Al)
- Fluorine (-1)
- Hydrogen (+1)
- Oxygen (-2)
- Chlorine (-1)