| | The Halogen Group | | | Across | | | 4. | | Discovered when too much sulfuric acid was accidentally added to seaweed ash. | | | 5. | | It is estimated that there is no more than 30 grams of this element in the earth's crust at any one time. | |
| | | Down | | | 1. | | This element is a liquid at room temperature. | | | 2. | | This element combines with an alkali metal to form table salt. | | | 3. | | This is the most reactive of all elements. | |
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