Across
- 3. anything that has mass and takes up space
- 6. a particle in the nucleus with no charge
- 8. life, the time it takes for half of a radioactive sample to decay
- 9. an atom that has gained or lost electrons
- 11. a state of matter with definite shape and volume
- 13. the dense center of the atom
- 15. a high-energy state of matter with charged particles
- 17. a reaction between fuel and oxygen that produces heat
- 18. replacement, a reaction where two compounds exchange ions
- 19. a substance present at the start of a reaction
Down
- 1. the smallest unit of an element
- 2. a state of matter with no definite shape or volume
- 4. a negatively charged particle outside the nucleus
- 5. a positively charged particle in the nucleus
- 7. decay, when an unstable nucleus breaks down
- 10. a reaction where a compound breaks into simpler substances
- 12. atoms of the same element with different numbers of neutrons
- 14. a state of matter with definite volume but no definite shape
- 16. a substance made in a chemical reaction