| A | B |
|---|
| atom | is the smallest particle into which an element can be divided and still be the same substance |
| theory | is a unifying explanation for a broad ranage of hythoptheses and observations that have been supported by testing |
| electrons | The negatively charged particles found in electron clouds outside the nucleus. The size of the electron clouds determines the size of the atom. |
| Model | is a representation of an object or system |
| nucleus | The postively charged enter of an atom. It contains most of the atom's mass. |
| Electron Cloud | Current theory- regions inside of an atom is where electrons are likely to be found. |
| atomic mass | is expressed by SI unit. It is the number of protons + the number of neutrons |
| neutrons | are particles of the nucleus that have no charge. |
| atomic number | The number of protons in the nucleus is the atomic number. |
| isotopes | are atoms that have the same number of protons but different numbers of neutrons. |
| mass number | is the sum of the protons and neutrons in an atom |
