Across
- 4. mnumber of protons contained in an atom's nucleus
- 6. positively charged center of an atom, made up of protons and neutrons and surrounded by electrons in energy levels
- 8. tiny atomic particle with little mass and a negative electric charge
- 9. tiny atomic particle that is electrically neutral and has about the same mass as a proton
- 10. tiny atomic particle that has mass and a positive electric charge
Down
- 1. an atom that has gained or lost an electron
- 2. combined number of protons and neutrons in the nucleus of an atom
- 3. an atom of an element that has a different mass number than the element but the same chemical properties
- 5. anything that has volume and mass
- 7. natural or artificial substance that cannot be broken down into simpler substances by physical or chemical means