Across
- 1. The smallest unit of matter that can exist independently
- 3. A vertical column on the periodic table
- 4. The mass of an atom
- 8. The negatively charged particles in an atom that orbit the nucleus
- 9. A substance made up of atoms of the same element
Down
- 1. The number of protons in an atom's nucleus
- 2. The positively charged particles in an atom's nucleus
- 5. The abbreviation for an element
- 6. The building blocks of all matter
- 7. A horizontal row of elements on the periodic table
- 10. The number of protons and neutrons in an atom's nucleus