| Term | Definition |
|---|---|
| matter | anything that takes up space and has mass |
| mass | the material that matter is made up of |
| volume | how much room/space matter takes up |
| density | D=m/v the amount of material/stuff matter takes up within a specific space |
| atom | the smallest unit of matter that builds up all matter |
| protons | positively charged particles in an atom's nucleus |
| neutrons | particles with no charge that accompany protons in the nucleus of an atom |
| electron | negatively charged particles that move around rapidly outside of an atom's nucleus and that has an attractive force that bonds atoms together |
| Periodic Table | A chart that classifies elements by their physical and chemical properties |
| element | makes up all matter in the universe, cannot be broken down, and is the simplest substance. |
| periods/rows | The rows that make up the Periodic Table and tell us how many energy levels an element has |
| groups or family/columns | The columns in the periodic table that tell us how many electrons are in an atoms outer energy level |
| valence electrons | The electrons in an atom's outer energy level |
| atomic number | The number of protons in an element, also usually determines the number of neutrons and electrons |
| atomic mass | The mass of an element's atoms |
| chemical property | The ability a substance has to combine with others to form new ones |
| physical property | includes a substance's appearance and state of matter. |
| ionic bond | This occurs when elements lose or gain an electron while bonding |
| covalent bond | this happens when elements share an electron while bonding |
| chemical change/reaction | this occurs when the electron's attractive force bonds two elements together creating a reaction or change |
| compound/molecule | two or more elements that combine in a set ratio making a whole new substance |
| mixture | two or more substances that are combined, but retain their properties and are not a whole new substance, thus not chemically combined |
| Nobel Gases | All of elements in Group #18 that are the most stable elements because they have eight valence electrons |
| Halogens | all elements in group #17 they are very reactive with elements in group #1 because they have 7 valence electrons and want to be stable |
| Alkali Metals | all elements in group #1- all have only one valence electron and are very reactive |
| Metalloids | elements with 3-7 valence electrons between metals and non-metals that can react either way |
| Endothermic | a chemical reaction that absorbs energy (decrease in temp) |
| Exothermic | a chemical reaction that produces energy (heats up) |
