| ASTATINE | Radioactive chemical element of the halogen series occurring as a decay product of uranium and thorium; atomic no. 85 (8) |
| PROTACTINIUM | Radioactive metallic element of the actinide series occurring as a decay product of uranium; atomic no. 91 (12) |
| BROMINE | Noxious red liquid element of the halogen series occurring in seawater, atomic no. 35 (7) |
| ACTINIUM | Radioactive metallic element that glows blue in the dark; a decay product of uranium (8) |
| NEODYMIUM | A toxic silvery-white metallic element of the lanthanide series, occurring principally in monazite |
| IRIDIUM | Chemical element of the platinum group with the atomic number 77 (7) |
| NEUTRON | Beta decay product, at times |
| AT | A highly unstable radioactive element (the heaviest of the halogen series) |
| FLUORINE | Toxic pale yellow gas of the halogen series that is the most reactive non-metallic element (8) |
| IODINE | A bluish-black element of the halogen group, the compounds of which are used in medicine, photography and dyes (6) |
| RADON | Gaseous chemical element formed by the radioactive decay of uranium and other metals; atomic no. 86 (5) |
| EMERALD | Occurring as a result of processes that happened over hundreds of millions of years, a green variety of beryl that is the traditional birthstone for May (7) |
| CHLORINE | Gaseous element of the halogen group |
| FLOURINE | Toxic as of the halogen group with the atomic number 9 (8) |
| EXANTHEMA | Skin rash occurring as a symptom of a disease such as measles or rubella (9) |
| GANGRENE | A decay of body tissue arising from a loss of blood supply (8) |
| BORON | Hard metalloid element occurring as a dark brown amorphous powder and black crystals; atomic number 5 (5) |
| PITCHBLENDE | Blackish mineral which is the principal source of uranium and radium (11) |
| BERKELIUM | Radioactive chemical element named after a city in California (9) |
| PLUTONIUM | Radioactive chemical element with the atomic number '94' (9) |
