Across
- 3. A chemical element represented by Na, reactive with water (6 letters)
- 6. A substance made up of only one type of atom (7 letters)
- 7. The smallest unit of a chemical element that retains its properties (4 letters)
- 9. The lightest gas that makes up about 78% of Earth's atmosphere (8 letters)
- 10. This gas is essential for respiration and forms water molecules (6 letters)
Down
- 1. This law states that mass cannot be created or destroyed in a chemical reaction (12 letters)
- 2. The law of definite ______ states that a compound always contains the same elements in the same ratio (10 letters)
- 4. A combination of two or more atoms bonded together (8 letters)
- 5. A measure of the amount of matter in an object (4 letters)
- 8. The smallest part of matter, as per ancient Greek philosophers (8 letters)