| A | B |
|---|
| matter | anything that has mass and takes up space |
| element | a substance that cannot be broken down by physical or chemical means |
| compound | a substance made of two or more elements chemically combined |
| atom | the smallest particle of an element |
| molecule | a combination of two or more elements |
| physical properties | property of matter that can be observed without changing the composition or identity of the matter |
| chemical properties | ability of a substance to change into a new substance with different properties by combining with other substances |
| physical change | a change in a substance that does not change the identity of the substance |
| chemical change | a change in which one or more substances combine or break apart to form a new substance |
| solid | a state of matter that has a definite shape and volume |
| liquid | a state of matter that has no definite shape, but has a definite volume |
| gas | a state of matter with no definite shape or volume |
| chemical reaction | a process in which substance undergo chemical changes forming a new substance with different properties |
| mixture | two or more substances that are mixed together but not chemically combined |
| solution | a very well-mixed mixture |
| periodic table | chart of the elements showing the repeating pattern of their properties |
| group | elements in the same vertical column of the periodic table |
| period | horizontal row of elements in the periodic table |
| atomic number | the number of protons in the nucleus of an atom |
| atomic mass | the average mass of one of the atoms of an element |
| proton | a small positively charged particle in the nucleus of an atom |
| neutron | a small particle in the nucleus of an atom with no electical charge |
| electron | a tiny negatively charged particle that moves around the nucleus of an atom |
| nucleus | the center core of an atom containing protons and neutrons |
| valance electrons | one of the electron farthest away from the nucleus involved in a chemical reaction |
