Across
- 2. fusion the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy
- 3. reaction a chemical reaction or other process in which the products themselves promote or spread the reaction, which under certain conditions may accelerate dramatically.
- 6. fission atoms are split apart, which releases energy.
- 9. particle composite particles consisting of two protons and two neutrons tightly bound together
- 10. number the total number of protons and neutrons in a nucleus.
- 11. particle is a fast-moving electron emitted by radioactive decay of substances.
- 12. number the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
Down
- 1. a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign.
- 2. A nucleus is a membrane-bound organelle that contains the cell's chromosomes.
- 4. The neutron is a subatomic particle, symbol n or n⁰ , which has a neutral charge, and a mass slightly greater than that of a proton.
- 5. the time taken for the radioactivity of a specified isotope to fall to half its original value.
- 7. the emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei.
- 8. radiation Gamma rays are similar to x-rays, but are very penetrating and are best stopped or shielded by dense materials, such as lead or depleted uranium.
- 13. Atoms with the same number of protons but different numbers of neutrons are called isotopes.