Across
- 3. Subatomic particle that has a negative charge
- 7. Unstable atoms (radioisotopes) emit radiation to become stable
- 10. Different forms of an element with the same number of protons but different number of electrons
- 11. the process of exposing an object to nuclear radiation
- 12. very dense and positive centre of an atom
- 13. Number of protons
- 17. A particle that has the same number of protons and electrons
- 18. Emits a electron
Down
- 1. Subatomic particle that has a positive charge
- 2. What is radiation measured in
- 4. Number of protons and neutrons
- 5. What is used to measure radiation
- 6. What a unstable radioactive substance decays
- 8. The unwanted presence of materials containing radioactive atoms on other materials
- 9. A particle that has a uneven amount of electrons and protons
- 13. emits a helium nucleus
- 14. Subatomic particle that has no charge
- 15. Emits a electromagnetic wave
- 16. time taken for half the active nuclei in a sample to decay