| A | B |
|---|
| nucleons | protons & neutrons |
| electron | negatively charged |
| proton | positively charged |
| atomic number | determines element type |
| atomic mass | total number of nucleons |
| number of protons | same as number of electrons in an uncharged atom |
| isotopes | same number of protons, different number of neutrons |
| positive ion | fewer electrons than protons |
| negative ion | more electrons than protons |
| atomic mass unit | approximate mass of a proton or neutron |
| average atomic mass | found on periodic table, an average which includes all isotopes |
| gram atomic mass | atomic mass expressed in grams |
| molar mass | equals gram atomic mass for 1 mole of an atom |
| ground state | when electrons are at the lowest possible energy level |
| excited state | when electrons have absorbed energy and moved to a higher energy level |
| n | principal quantum number = principal energy level |
| n^2 | number of orbitals allowed |
| 2 electrons | allowed in each orbital |
| n again | number of sublevels (s, p, d, f) allowed |
| emission spectra | seen when electrons go from the excited state to the ground state |
| bright line spectra | emission spectra |
| dark line spectra | absorbtion spectra |
| absorbtion spectra | seen when electrons go from the ground state to the excited state |
| valence electrons | electrons in the outer s and p subshells |
| Lewis dots | represent valance electrons |
| kernel or core | short cut to represent inner electrons |
| alpha particle | helium nucleus |
| beta particle | electron |
| gamma ray | high energy radiation |
| stopped by paper | alpha particle |
| stopped by cardboard | beta particle |
| stopped only by lead | gamma ray |
| transmutation | when an atom of one element forms an atom of another element by radioactive decay |
| half life | after one half life 1/2 the original element has decayed |
| ionization energy | energy required to remove one electron from an atom |
| electron configuration | lists the positions of all electrons in an atom by energy level and sublevel |
| find the number of neutrons | subtract atomic number from atomic mass |
| positive | charge on a proton |
| negative | charge on an electron |
| neutral | charge on a neutron |
