| Answer | Crossword Clue |
|---|---|
| IONIUM | Radioactive element discovered in 1907. |
| POLONIUM | Radioactive element in pitchblende. |
| PLUTONIUM | Radioactive element isolated in 1940. |
| ACTINIUM | Radioactive element that glows blue in the dark |
| EINSTEINIUM | Element discovered in 1952 |
| ERBIUM | Element discovered in 1843 |
| BORON | Element discovered in 1812 |
| RADIUM | Element discovered in 1898 |
| NEON | Element discovered in 1898 |
| RADIUM | Metallic element discovered in 1902. |
