Assigning Oxidation Numbers

Front

What is an oxidation number?

Back

The oxidation number (or oxidation state) is a value that represents the total number of electrons that an atom either gains or loses in order to form a chemical bond.

Front

What is the oxidation state of oxygen in most compounds?

Back

-2

Front

What is the oxidation state of hydrogen in most compounds?

Back

+1

Front

What is the oxidation state of alkali metals in compounds?

Back

+1

Front

What is the oxidation state of alkaline earth metals in compounds?

Back

+2

Front

What is the oxidation state of halogens in compounds?

Back

-1, except when combined with oxygen or other halogens.

Front

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

Back

The sum of the oxidation numbers in a neutral compound is equal to zero.

Front

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

Back

The sum of the oxidation numbers in a polyatomic ion is equal to the charge of the ion.

Front

What is the oxidation state of phosphorus in Mg3(PO4)2?

Back

+5

Front

What is the oxidation state of sulfur in Al2(SO4)3?

Back

+6