| A | B |
|---|
| atom | Smallest possible particle of matter. |
| atomic number | Number of protons in the nucleus of an atom. |
| chemist | Scientist who studies matter, how it is put together, what it is made of, and how it acts. |
| chemistry | Science which studies matter and how it changes. |
| compounds | Substances which can be broken down into other substances, such as dihydrogen monoxide. |
| elements | substances which are the basic building blocks of all matter, made of only one kind of atom. |
| mass | Amount of matter in something, which can be measured with a balance or scale. |
| matter | Anything which takes up space and has mass. |
| mixture | A combination of different kinds of matter, in which the different kinds are not changed by being put together. |
| molecule | Two or more atoms held together by a chemical bond. |
| property | A way of describing matter, such as color, mass, or density. |
| reaction | Chemical change in which two or more substances form new substances. |
| science | A way of learning knowledge which uses careful methods to test ideas and observations |
| substance | Something made of only one kind of matter, only one kind of molecule or atom. |
| volume | The amount of space something takes up. |
| nucleus | Center of an atom |
| neutron | Particle in the center of the atom which has no charge. |
| proton | Particle in the center of the atom which has a positive charge. |
| electron | Particle which orbits the nucleus of the atom and has a negative charge. |
| subscript | Number written to the right and below a chemical symbol to show how many atoms of that element are in a molecule. |
| physical change | A change which does not form new kinds of matter, such as melting or breaking. |
| chemical change | Change which forms new kinds of matter, such as burning or rusting. |
| subatomic particles | Tiny bits of energy which make up the atom. |
| hypothesis | An if-then statement of what should happen, based on an inference. |
| inference | A possible explanation of an observation. |
| observation | Evidence that is gotten directly through the senses or a measuring instrument. |
