Across
- 3. have two or more elements in their structure.
- 5. a substance that cannot be broken down into smaller components through chemical reactions.
- 6. everything in the universe is made of this.
Down
- 1. the smallest particle of an element that still has all its properties.
- 2. have two or more atoms of the same element in their structure.
- 4. has definite physical properties and a definite chemical composition.