| Answer | Crossword Clue |
|---|---|
| HYDROGEN | Element in water |
| OXYGEN | Element in water |
| CHLORIN | Element used in purifying water. |
| IODINE | Element occurring in sea water. |
| SODIUM | Element lighter than water. |
| BROMINE | Element from sea water |
| FLUORIDATES | Adds an element to drinking water. |
