| A | B |
|---|
| Hund's Rule | states that orbitals of the same n and l quantum nunmbers are each occupied by one electron before any pairing occurs |
| aufbau principle | states that orbitals fill up lowest energy levels first |
| Pauli exclusion principle | states that no two electrons in the same atom can have the same four quantum numbers |
| law of multiple proportions | states that if two or more different compounds are composed of the same two elements, the ratio of the masses of the second element is always a ratio of the small whole number |
| law of conservation of mass | states that the mass of the reactants is equal to that of the products |
| law of definate proportions | states that two samples of a given compound are made of the same elements in exactly the same proportions by mass regardless of the sizes or sources of the sample |
| quantum numbers | the numbers that define the region in which electrons can be found |
| orbitals | regions around a nucleus that correspond to specific energy levels |
