Radiation

3. The basic unit of matter consisting of a nucleus surrounded by electrons.
9. The antimatter counterpart of the neutrino, emitted during beta minus decay.
11. A fundamental particle that combines with other quarks to form protons and neutrons.
12. The antimatter equivalent of an electron; it has the same mass as an electron but a positive charge.
14. The dense central region of an atom containing protons and neutrons.
17. A collective term for the particles found in the nucleus: protons and neutrons.
18. An uncharged particle found in the nucleus of an atom.
21. A particle with no charge and extremely small mass emitted during beta plus decay.
22. Radiation High-energy electromagnetic radiation emitted from an excited nucleus.
23. Quark A type of quark with a charge of +2/3 that is found in protons and neutrons.
24. Plus Particle A positron emitted when a proton changes into a neutron.

1. Particle A particle consisting of two protons and two neutrons, equivalent to a helium nucleus.
2. Decay The process by which an unstable nucleus transforms into a more stable nucleus by emitting radiation.
4. Stability The condition in which a nucleus remains intact because the strong nuclear force balances proton repulsion.
5. A negatively charged particle that exists outside the nucleus.
6. Repulsion The force that causes positively charged protons to repel one another.
7. A positively charged particle found in the nucleus of an atom.
8. Quark A type of quark with a charge of –1/3 that is found in protons and neutrons.
10. The spontaneous emission of radiation from an unstable nucleus.
13. Nuclear Force The powerful attractive force that holds protons and neutrons together in the nucleus.
15. of Charge The principle that total electric charge remains the same before and after a nuclear reaction.
16. A specific type of nucleus characterised by its number of protons and neutrons.
19. Minus Particle A high-speed electron emitted when a neutron changes into a proton.
20. Atoms of the same element that have the same number of protons but different numbers of neutrons.