| A | B |
|---|
| matter | anything that has volume and mass |
| element | A substance that cannot be broken down into simpler substances by physical or chemical means |
| nucleus | the center of an atom, made up of protons and neutrons |
| proton | a particle with mass and a positive electric charge |
| neutron | a particle with about the same mass as a proton but with no electrical charge |
| electron | a particle with little mass and a negative charge |
| atomic number | the number of protons in an atom's nucleus |
| mass number | the combined number of protons and neutrons in an atom |
| isotopes | atoms of the same element with different mass numbers |
| ion | an atom that gains or loses an electron with a net electric charge |
| region | a continuous part of a surface or space or body, with or without definite boundaries or with certain characteristics |
| compound | a substance that is composed of atoms of two or more different elements that are chemically combined |
| chemical bond | the forces that hold elements together in a compound |
| covalent bond | the attraction of two atoms for a shared pair of electrons that hold the atoms together |
| molecule | units of two or more atoms held together by covalent bonds |
| ionic bond | the attractive force between two ions of opposite charge |
| metallic bond | allows electrons to move freely and conduct electricity |
| chemical reaction | the change of one or more substances into other substances |
| solution | a mixture in which the component particles retain their original properties, but cannot be distinguished |
| acid | a substance that produces hydrogen ions in water |
| base | a substance that produces hydroxide ions in water |
| scientific law | a basic principle that describes the behavior of a natural phenomenon |
| crystalline structure | a structure in which the particles are arranged in regular geometric patterns |
| glass | solids that consist of densely packed atoms arranged at random |
| evaporation | the process of change of the state of matter from a liquid to a gas |
| plasma | a state of matter consisting of hot, highly ionized, electrically conducting gases |
| condensation | the process of change of a state of matter from a gas to a liquid |
| sublimation | the change of state from a solid to a gas without an intermediate liquid state |
