Across
- 4. ____ number. The number of protons an atom has. Physicists say proton number.
- 7. ____ number. The number of protons + neutrons in an atom.
- 8. Radiation that is ever-present around us, e.g. medical uses, from cosmic rays, nuclear weapons fallout etc.
- 9. Use a periodic table. What element has 7 protons?
- 12. Alpha, beta and gamma (and neutron) are ________ radiation that can knock electrons off atoms to make ions.
- 14. Stopped by paper or a few cm of air. Same as a helium nucleus (2 protons 2 neutrons).
- 18. Nuclear decay is _____; you cannot predict when when nucleus will decay.
- 20. I have the same mass as a proton but I am uncharged. What am I?
- 22. The force between nuclei that prevents them from fusing (you need very high temperatures to overcome this).
- 24. This is measured in Becquerels. It's the number of radioactive decays per second.
- 25. The word for where just the neutrons and protons are located.
- 28. _____ rod. Used in fission reactors to maintain a stable reaction rate.
- 29. Mass = 1/1800 amu, Charge = -1. Orbit in discrete energy levels (shells).
- 30. (TwoWords). A common detector of radiation, ____-____ tube. Named after two famous physicists.
- 32. Abbreviation for the medical diagnosis machine that makes use of beta+ decay and annihilating electrons and positrons.
Down
- 1. I'm a very penetrating type of radiation. I'm an electromagnetic wave. Lead just about stops me.
- 2. Place in Russia (now Ukraine) where, in 1986, a nuclear fission power plant suffered a catastrophic meltdown.
- 3. reaction in a fission bomb/reactor is when neutrons cause uranium to fiss, releasing more neutrons, etc
- 5. Radioactive isotope with a short half-life injected into someone as a diagnosis tool. Also in pipelines. Uses gamma emmiters.
- 6. When a heavy nucleus (e.g. uranium) splits up due to neutron bombardment and releases lots of energy.
- 10. Beta- radiation can be used to control the _______ of paper/thin foil when it is made.
- 11. A few .......... The range of alpha particles in air.
- 13. A radioactive isotope of this element is responsible for most of the background radiation we are subject to.
- 15. (TwoWords). The time it takes for half the nuclei in a radioactive sample to decay.
- 16. ____ alarm. A use of alpha radiation every household should have.
- 17. Antielectron (beta+)
- 19. I'm positive, I live in the nucleus, I have a mass of 1 amu. What am I?
- 21. Units with the abbreviation Bq (used for rate of decay or "activity").
- 23. When two small nuclei (e.g. hydrogen) combine and release massive amounts of energy.
- 26. What you may develop if you receive too high a dose of radiation.
- 27. Number as a word (unit is days). If a number of radioactive nuclei falls to 1/16th in 20 days, how long is the half-life?
- 31. Same number of protons, different number of neutrons e.g. Li-6 and Li-7.