| Answer | Crossword Clue |
|---|---|
| BOMBS | Atom and hydrogen |
| NEUTRON | Hydrogen-atom lack |
| PROTON | A hydrogen atom has one |
| GASES | Hydrogen and oxygen |
| GASSES | Hydrogen and methane |
| GASES | Hydrogen and helium |
| GASES | Neon and hydrogen |
| GASES | Helium and hydrogen |
| GASEOUS | Like hydrogen and chlorine |
| GASSES | Hydrogen and methane (Var.) |
| GASES | Hydrogen and oxygen, e.g. |
| ISOTOPES | Deuterium and tritium, to hydrogen |
