Oxidation Numbers

Front

What is an oxidation number?

Back

An oxidation number is a value assigned to an element in a compound that represents the number of electrons lost or gained by that element during a chemical reaction.

Front

What is the oxidation number of an element in its elemental form?

Back

The oxidation number of an element in its elemental form is always 0.

Front

What is the oxidation number of oxygen in most compounds?

Back

The oxidation number of oxygen in most compounds is -2.

Front

What is the oxidation number of hydrogen in most compounds?

Back

The oxidation number of hydrogen in most compounds is +1.

Front

What is the oxidation number of alkali metals in compounds?

Back

The oxidation number of alkali metals (Group 1) in compounds is always +1.

Front

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

Back

The oxidation number of alkaline earth metals (Group 2) in compounds is always +2.

Front

How do you determine the oxidation number of an element in a compound?

Back

To determine the oxidation number of an element in a compound, use the known oxidation states of other elements in the compound and apply the rule that the sum of oxidation numbers in a neutral compound must equal zero.

Front

What is the oxidation number of chlorine in ClO₃^-1?

Back

The oxidation number of chlorine in ClO₃^-1 is +5.

Front

What is the oxidation number of sulfur in H₂SO₄?

Back

The oxidation number of sulfur in H₂SO₄ is +6.

Front

What is the oxidation number of nitrogen in NH₃?

Back

The oxidation number of nitrogen in NH₃ is -3.