Oxidation Number Rules

AP Chemistry

0

What is the oxidation number of an uncombined element?

Equal to its charge

What is the oxidation number of a monatomic ion?

The more electronegative element

In a binary compound, which element gets the negative oxidation number?

-1 (always)

What is the oxidation number of fluorine in compounds?

-2 (+2 when bonded with fluorine / -1 in peroxides)

What is the usual oxidation number of oxygen?

+1 (-1 when bonded with metals)

What is the oxidation number of hydrogen?

+1

What is the oxidation number of Group 1 elements in compounds?

+2

What is the oxidation number of Group 2 elements in compounds?

+3

What is the oxidation number of aluminum in compounds?

0

What is the sum of oxidation numbers in a neutral compound?

Equal to the charge of the ion

What is the sum of oxidation numbers in a polyatomic ion?