| A | B |
|---|
| atom | building block of matter |
| matter | anything that has volume and takes up space |
| proton | subatomic particle that is located in the nucleus and weighs 1 amu |
| neutron | subatomic particle located in the nucleus and weighs 1 amu |
| electron | subatomic particle located outside the nucleus and weighs 1/1836 amu |
| nucleus | center of atom made up of protons and neutrons |
| element | a substance that cannot be broken down chemically into other substances |
| compound | a combination of two or more different atoms |
| atomic number | number of protons in a nucleus |
| mass number | sum of protons and neutrons in a nucleus |
| isotope | atoms of the same element that have the same number of protons but different numbers of neutrons |
| neutral atom | smae number of protns and electrons |
| valence electrons | electrons in the outer energy level that influence how the atom interacts with other atoms |
| chemical bonding | combining of atoms to form new substances |
| 2 | number of electrons in the first energy level of an atom |
| 8 | number of electrons in the second energy level of an atom |
| ionic bond | formation of crystals between opositely charged ions |
| ion | charged atom |
| covalent bond | electrons are shared |
| chemical change | marked by formation of a precipitate, gas, or color change) |
| physical change | marked by change in state, shape, or size |
