| 1 | Atoms differ in their atomic weights. | |
| 2 | A hydrogen molecule consists of only two hydrogen atoms with the same atomic weight. | |
| 3 | All uranium atoms do not have the same atomic weight. Some of them weigh 234 units, some (of them) (weigh) 235 units, and some (of them ) (weigh) 238 units. | |
| 4 | Electrons weigh very little, so they aren't even counted in the atomic weight. | |
| 5 | An arrangement of 56 elements in order of ascending atomic weight made by Newlands in 1863. |