Chapter 1-7: Oxidation Numbers and Redox (Vocabulary Flashcards)

Vocabulary flashcards covering core terms and rules related to oxidation numbers and redox chemistry from the notes.

Nonmetal oxide

An oxide formed from a nonmetal; reacts with water to form an acid.

Metal oxide

An oxide of a metal; typically forms basic solutions when dissolved in water.

Hydride

A compound in which hydrogen has a -1 oxidation state (often with a metal); hydrogen behaves as H− in metal hydrides.

Hydroxide

The OH− anion; a basic component found in many bases.

Acid (from nonmetal oxide and water)

A substance formed when a nonmetal oxide reacts with water, producing an acidic solution (contains H+ in solution).

Redox reaction

A reaction in which electrons are transferred, causing changes in oxidation states of atoms.

Oxidation

Loss of electrons; increase in oxidation state.

Reduction

Gain of electrons; decrease in oxidation state.

Oxidation number

A formal charge assigned to an atom to track electron transfer in bonding; not always equal to the actual charge.

Natural state

Oxidation number of elements in their elemental form is zero.

Peroxide

A compound with an O–O single bond; oxygen in peroxides has an oxidation number of −1.

Oxygen oxidation number rule

Oxygen is typically −2 in compounds; in peroxides it is −1.

Hydrogen oxidation state rule

Hydrogen is usually +1 in compounds; in metal hydrides it can be −1.

Metal oxidation number equals charge

In many compounds, the metal’s oxidation number equals its ionic charge (e.g., Ca2+ = +2 in compounds).

Sum of oxidation numbers

The sum of oxidation numbers in a neutral compound is 0; in an ion it equals the ion’s overall charge.

Ammonium ion

NH4+, a polyatomic cation with a +1 overall charge.

Dichromate ion

Cr2O7^2−, a polyatomic anion with a −2 overall charge.

Water oxidation numbers

In H2O, hydrogen is +1 and oxygen is −2; the molecule is neutral overall.

Nitrate ion

NO3−, a polyatomic anion with a −1 overall charge.