2. For nuclear energy the atomic number is below the symbol.
3. The proton number determines the kind of element.
4. Alpha, beta, and gamma rays are given off by radioactive elements.
5. Particles coming from beyond our atmosphere are cosmic rays.
6. Radioactive elements change until lead is formed.
7. Fission occurs when atoms break apart.
8. Fusion occurs when hydrogen atoms combine together.
9. Pathways of invisible particles can be observed by using a cloud chamber.
10. If an element has a half-life of 250 years, how much of 2 grams will be left after 500 years?
.5 grams.
11. Alpha rays consist of helium nuclei.
12. Helium has a mass of 4 and atomic number of 2.
13. An atomic bomb explodes when fission and a chain reaction occur at the same time.
14. When an element has a ratio of 1:1 for protons and neutrons, it is stable.
15. Lead and thick concrete will stop gamma rays.
16. A geiger counter detects radioactive particles.
17. Atoms of one element can change into atoms of another element. This is called Transmutation.
18. Elements have different half-lives.
19. Chain reactions occur during fission.
20. Fusion is more efficient than fission.
21. Electrons are not rearranged during nuclear change. Rearrangement of electrons occurs during a chemical change.
22. Fission can be used to produce electricity.
23. Nuclear reactions are not affected by pressure and temperature.
24. Tremendous amounts of energy are released during fission and fusion.
*Changes within the nucleus of an atom are responsible when an element changes.*
*Particles that are radioactive are given off.*
*Alpha, beta, and gamma rays leave the atom.*
*Gamma rays are the most dangerous to living things. These rays may be observed using a cloud chamber.*
*A nuclear reactor provides controlled energy.*
*Uranium undergoes nuclear change.*
*A chained reaction occurs very rapidly. This is fission.*
*Hydrogen atoms unite to form helium atoms. The hydrogen bomb is an example of fusion.*
*The process also occurs in our sun. Matter is converted to energy.*
*Cosmic rays come from outer space. They make up part of normal background radiation.