| # | Concept | Culture | Statement | Freq. |
|---|---|---|---|---|
| 1 | protium | physics | Protium is the most common isotope of hydrogen, with one proton and no neutrons. | 1 |
| 2 | protium | physics | In chemistry and physics, protium is studied as the simplest and most abundant hydrogen isotope. | 1 |
| 3 | protium | physics | Protium is the most common isotope of hydrogen, with a single proton and no neutrons. | 1 |