| A | B |
|---|
| chemical symbol | abbreviated way to write the name of an element |
| nucleus | positively charged center of an atom |
| electron | negatively charged particle that surrounds the nucleus of an atom |
| proton | positively charged particle found in the nucleus of an atom |
| neutron | neutrally charged particle found in the nucleus of an atom |
| atomic number | the number of protons in an atom |
| electron cloud | region surrounding the nucleus where an electron is likely to be at any time |
| mass number | the sum of the protons and neutrons in the nucleus of an atom |
| isotopes | atoms of the same element that have different numbers of neutrons |
