| Rating | Solver | Clue |
|---|---|---|
| NEON | Atomic number 10 | |
| OXYGEN | Its atomic number is 8 | |
| BORON | Chemical element with the symbol B and atomic number 5 | |
| ISOTOPE | One of two or more atoms with the same atomic number that contain different numbers of neutrons | |
| ATOMICITY | Degree of atomic attraction; equivalence; valence; also (a later use) the number of atoms in an elementary molecule. See Valence. | |