The part of an atom that contains the subatomic particles that contribute to the atomic mass .

A negatively charged subatomic particle that moves around the nucleus of an atom.

An area surrounding the nucleus of an atom where electrons are likely found .

A particle in the nucleus of an atom that has a positive charge .

A pure substance, made of atoms, that cannot be broken down into simpler substances by physical or chemical means.

The smallest particle of an element that has all the properties of that element.

The smallest complete unit of a compound with the same properties as the compound .

A particular kind of matter.

Relating to the physical composition of an object.

An ordered arrangement of the elements according to atomic number.

A number to the left of a chemical symbol or formula of a substance

Anything that takes up space and has mass.

A small symbol to the right of an element that identifies how many of the elements are present.

An electron in the outer shell of an atom that can combine with other atoms to form chemical bonds.

A way of describing a chemical reaction using chemical formulas and symbols.

A way of describing a substance using chemical symbols and numbers.

The characteristics of a substance as it reacts with others to form new substances with different properties

A process in which one or more substances react to produce one or more new substances.

Law that states matter cannot be created or destroyed in a closed system.