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| International System of Units | a system of measurement based on multiples of ten and on established measures of mass, length, volume, and time |
| atom | the smallest component of an element having the chemical properties of the element |
| chemical bond | a force that holds two atoms together |
| chemical change | a change in which new or different kinds of matter are formed |
| chemical property | a characteristic that can be observed when a substance interacts with something else |
| chemistry | the study of the properties of matter and how matter changes |
| compound | a substance that is made up of two or more elements chemically joined together |
| density | measurement of how much mass is contained in a given volume of an object |
| electron | particle of an atom with a negative charge |
| element | substance that cannot be broken down into simpler substances and whose atoms are exactly alike |
| energy | the ability to do work or cause change |
| mass | amount of matter in an object |
| matter | anything that takes up space and has mass |
| mixture | made from two or more substances (elements, compounds, or both) that are in the same place but are not chemically combined |
| molecule | particle which is made up of two or more atoms which are bonded together |
| neutron | particle in an atom that has no charge |
| nucleus | the center core of the atom |
| physical change | a change that alters the form or appearance of a material but does not make the material into another substance |
| physical property | a characteristic of a substance that can be observed without changing the substance into something else |
| proton | a positively charged particle in the nucleus of an atom |
| state | the three forms of matter (liquid, solid, and gas) |
| substance | a single kind of matter that has distinct physical and chemical properties |
| volume | the amount of space that an object occupies |
| weight | the measure of the force of gravity on an object |
| Democritus | Greek philosopher who believed that matter could be divided into smaller smaller pieces until the smallest piece would be reached - e named te smallest piece atom, meaning "indivisible" |
| Jon Dalton | scientist who came up with the atomic theory |
