Science

2. an electron or positron emitted from an atomic nucleus in a certain type of radioactive decay.
4. a subatomic particle of about the same mass as a proton but without an electric charge
5. a reaction that results in a product necessary for the continuance of the reaction.
6. the integer nearest in value to the atomic weight of an atom and equal to the number of nucleons in the nucleus of the atom
8. a positively charged elementary particle that is a fundamental constituent of all atomic nuclei
10. a positively charged particle consisting of two protons and two neutrons, emitted in radioactive decay or nuclear fission; the nucleus of a helium atom.
11. he time required for one half the atoms of a given amount of a radioactive substance to disintegrate.
13. a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.

1. a nuclear reaction in which a heavy nucleus splits spontaneously or on impact with another particle, with the release of energy.
3. the number of positive charges or protons in the nucleus of an atom of a given element
7. electromagnetic radiation emitted by atomic nuclei
9. the central and most important part of an object
12. any of two or more forms of a chemical element
14. the phenomenon, exhibited by and being a property of certain elements, of spontaneously emitting radiation resulting from changes in the nuclei of atoms of the element.