Across
- 2. particles of matter, Atoms
- 4. was the first one to use picture symbols to denote, John Dalton elements
- 5. of only one type of atom, Elements
Down
- 1. with positive or negative charges, Radicals
- 3. of oxygen, Two
- 5. be separated into constituents by simple physical methods, Mixture
- 6. supporter of inflammable gas, Oxygen