| A | B |
|---|
| atom | smallest particle of an element that still has the properties of that element. |
| nucleus | the part of the atom that has most of the mass of the atom and that has a positive charge |
| proton | a positively charged paticle in the nucleus of an atom |
| neutron | a particle with no charge,also found in the atom's nucleus |
| electron | a negatively charged particles in the atom |
| atomic number | the number of protons in the nucleus of an atom of an element |
| mass number | the sum of the protons and neutrons in an atom |
| isotopes | atoms of the same element with different numbers of nuetrons |
| atomic mass unit | one-twelfth the mass of a carbon-12 atom |
| atomic mass | the mass of an atom in relation to the carbon 12 atom |
| chemical symbol | is a notation of one or more letters that representsan element |
| periodic table | elements are arranged in order of increasing atomic number |
| periodic law | states that the properties of the elements form the pattern if the elements arranged by increasing atomic number |
| group | is made up of elements that have similar chemical properties |
| period | each horizontial row in the periodic tabel |
