| A | B |
|---|
| atom | The smallest particle of an element that has the same properties of that element |
| nucleus | part of atom with the most mass and positive charge |
| proton | positively charged atom particle found in the nucleus |
| electron | negatively charged atom particle found outside the nucleus |
| atomic number | the number of protons found in the nucleus of an atom |
| mass number | the sum of the protons and neutrons in an atom |
| isotopes | atoms of same element with a different number of neutrons |
| atomic mass unit | (amu) 1/12 the mass of a carbon-12 atom |
| atomic mass | the mass of an atom in relation to the carbon-12 atom |
| chemical symbol | a notation of one or more letters that represents an element |
| Periodic Table | table that arranges elements by increasing atomic number |
| group | vertical columns of elements in a periodic table that have similar chemical properties |
| period | horizontal rows of elements in a periodic table |
| neutron | atom particle found in the nucleus with no charge |
