a measure of the amount of matter that an object contains; the SI mass unit of mass is the kilogram

a measure of the space occupied by a sample of matter

a property that depends on the amount of matter in a sample

a property that depends on the type of matter in a sample, not the amount of matter

the simplest form of matter that has a unique set of properties; an element cannot be broken down into simpler substances by chemical means

a substance that contains two or more elements chemically combined in a fixed proportion

a change that produces matter with a different composition than the original matter

a substance present at the start of a reaction

a substance produced in a chemical reaction

in any physical change or chemical change, mass is conserved; mass can be neither created nor destroyed

a neutral group of atoms joined together by covalent bonds

a tightly bond group of atoms that behaves as a unit and has a positive or negative charge

the ratio of the mass of an object to its volume

atoms of the same element that have the same atomic number but different atomic masses due to a different number of neutrons

the modern description, primarily mathematical, of the behavior of electrons in atoms

when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties

any atom or group of atoms with a positive charge

any atom or group with a negative charge

atoms react by gaining or losing electrons so as to acquire the stable electron structure of a noble gas, usually 8 valence electrons