| A | B |
|---|
| John Newlands | Law of Octaves |
| Johann Döbereiner | triads |
| Dmitri Mendeleev | developed structure of modern periodic table |
| Henry Mosely | ordered the periodic table by atomic number |
| Linus Pauling | devised the commonly used electronegativity scale |
| periods | series |
| groups | families |
| atomic radius | distance from the atom's nucleus to its outermost electron |
| first ionization energy | energy required to remove the first electron from its outermost shell |
| electron affinity | energy change when an electron is added to a neutral atom to produce an anion |
| electronegativity | the measure of the attraction between the nucleus and valence electrons of atoms bonded in molecules |
| descriptive chemistry | the study of elements and the compounds they form |
