a very small particle that makes up most kinds of matter and consists of smaller parts called protons, neutrons, and electrons

• atom

• electron

• matter

• neutron

average mass of an atom of an element; its unit of measure is the atomic mass unit (u)

• atomic number

• atomic mass

• isotope

• mass number

number of protons in the nucleus of each atom of a given element; is the top number in the periodic table

• atomic mass

• mass number

• atomic number

• isotope

a substance produced when elements combine and whose properties are different from each of the elements in it

• element

• matter

• mixture

• compound

invisible, negatively charged particle located in a cloud like formation that surrounds the nucleus of an atom

• electron

• proton

• neutron

• nucleus

natural or synthetic material that cannot be broken down into simpler materials by ordinary means; has unique properties and is generally classified as a metal, metalloid, or nonmetal

• compound

• element

• mixture

• atom

two or more atoms of the same element that have different numbers of neutrons in their nuclei

• atom

• compound

• isotope

• substance

states that matter is not created or destroyed but only changes form

• substance

• atomic number

• mass number

• law of conservation of matter

sum of the number of protons and neutrons in the nucleus of an atom

• mass number

• atomic number

• isotope

• atom

anything that takes up space and has mass

• atom

• substance

• matter

• element