Chem/Phys REDOX

oxidation

loss of electrons

reduction

gain of electrons

law of conservation of charge

electrical charge can be neither created nor destroyed; oxidation and reduction must occur simultaneously, resulting in an electron transfer called a redox reaction

oxidizing agent

causes another atom in a redox reaction to undergo oxidation and is itself reduced

reducing agent

causes the other atom to be reduced and is itself oxidized

LEORA says GEROA

Loss of Electrons is Oxidizing (Reducing Agent), Gain of Electrons is Reduction (Oxidizing Agent)

Oxidizing agents

almost all contain oxygen or another strongly electronegative element (such as a halogen)

reducing agents

often contain metal ions or hydrides (H-)

what is the oxidation number of a free element?

0

what is the oxidation number for a monatomic ion?

it is equal to the charge of the ion

what is the oxidation number of each group IA element?

+1

what is the oxidation number of each group IIA element?

+2

what is the oxidation number of each group VIIA element?

-1 except when combined with an element of higher electronegativity

what is the oxidation number of hydrogen?

usually +1; however, its oxidation number is -1 in compounds with less electronegative elements (group IA and IIA)

what is the oxidation number of oxygen?

in most compounds -2. perioxides (O₂^2-) for which the charge on each oxygen is -1, and compounds with more electronegative elements, such as OF₂, which oxygen has a +2 charge