Across
- 6. a pure substance made of on type of atom
- 7. Horizontal row on the periodic table
- 9. two or more atoms chemically bonded together
- 10. the smallest particle of an element
- 11. two or more different elements chemically bonded in a fixed ratio
- 12. two or more substances physically combined
Down
- 1. shell in which electrons are found around the nucleus
- 2. number of electrons gained, lost or shared by an atom
- 3. group 17 elements on the periodic table
- 4. number of protons in an atom
- 5. Vertical column on the periodic table
- 8. positively charged sub-atomic particle