Across
- 3. Substance used to cause a chemical reaction
- 5. Elements that have the same atomic number but different number of neutrons
- 9. the base unit of amount of a substance as determined by the International System of Units
- 10. The most reactive group of metals on the periodic table
- 11. Electrons in the outermost shell of an atom
- 13. A substance composed of two or more chemical elements
Down
- 1. The smallest unit of matter that forms a element
- 2. The part of the atom with a positive charge
- 4. The least reactive group on the periodic table
- 5. An atom that has lost or gained one or more electrons
- 6. The results of a chemical reaction
- 7. Where the protons and neutrons are found in a atom
- 8. The heaviest part of an atom
- 12. The smallest part of an atom