| Answer | Crossword Clue |
|---|---|
| protoactinium | a radioactive element that yields actinium on disintegration |
| protoactiniums | PROTOACTINIUM, a radioactive element that yields actinium on disintegration |
| francium | a short-lived radioactive element of the alkali-metal group occurring naturally as a disintegration product of actinium and also produced artificially see element table |
| franciums | a short-lived radioactive element of the alkali-metal group occurring naturally as a disintegration product of actinium and also produced artificially see element table |
