Across
- 2. Time for half of radioactive atoms to decay.
- 4. Weighted average mass of isotopes in periodic table.
- 7. Illness from excessive radiation exposure.
- 10. -1 charge, negligible mass, orbits nucleus.
- 12. Atoms of same element with different neutron numbers.
- 13. +1 charge, mass of 1, found in nucleus.
- 15. Arrangement of electrons in shells around nucleus.
- 17. Electron emission, moderate penetration.
- 20. Helium nucleus emission, weak penetration.
- 21. Dense core of atom, contains protons and neutrons.
- 22. Unstable atoms emit radiation, change into new elements.
- 24. Cancer treatment using targeted radiation.
Down
- 1. Energy levels where electrons orbit the nucleus.
- 3. Elements with metal and nonmetal properties.
- 5. Negatively charged ion, gained electrons.
- 6. Device measuring radiation levels.
- 8. Number of protons in an atom, determines element.
- 9. Total number of protons and neutrons in nucleus.
- 11. Positively charged ion, lost electrons.
- 14. High-energy electromagnetic wave, strong penetration.
- 16. 1986 nuclear disaster, severe radiation effects.
- 18. No charge, mass of 1, found in nucleus.
- 19. Horizontal rows in periodic table, increasing energy levels.
- 23. Vertical columns in periodic table, same valence electrons.