Across
- 4. A substance that cannot be broken down
- 5. The center of an atom made up of protons and neutrons.
- 6. Atoms of the same element that have different mass numbers
- 7. Number The number of protons in an atom’s nucleus
- 9. A tiny particle that has mass and a positive electric charge
Down
- 1. A negative electric charge that is exactly the same magnitude as the positive charge of a proton
- 2. Anything that has volume and mass
- 3. Number The sum of the protons and the neutrons in an atom’s nucleus
- 5. A tiny particle with approximately the same mass as a proton
- 8. An atom that gains or loses one or more electrons