redox

the loss of electrons meaning an increase in the oxidation number

the gain of electrons which will decrease the oxidation number

1- all uncombined elements have an oxidation number of 0 2- the oxidation numbers of the elements in a compound add up to zero 3- the oxidation number of a monochromatic ion is equal to the ionic charge 4- the sum of the oxidation number in an ion is equal to the charge on the ion 5- several elements have invariable oxidation numbers in their common compounds

1-group 1 metals always +1 2-group 2 metals always + 2 3- fluorine is always -1 4-hydrogen usually +1 except in metal hydrides 5- oxygen usually -2 unless peroxides or fluorine

electron donors

electron acceptors