| A | B |
|---|
| nuclear reaction | A reaction involving the particles in the nucleus of an atom that can change one element into another element. |
| isotope | An atom with the same number of protons and different number of neutrons from other atoms of the same element. |
| mass number | The sum of the protons and neutrons in the nucleus of an atom. |
| radioactive decay | The process in which the atomic nuclei of unstable isotopes release fast-moving particles and energy. |
| nuclear radiation | Particles and energy produced during radioactive decay. |
| alpha particle | A form of nuclear radiation consisting of two protons and two neutrons. |
| beta particle | An electron that is given off by a nucleus during radioactive decay. |
| gamma radiation | A form of nuclear radiation consisting of high-energy waves. |
| half-life | The length of time needed for half the atoms of a radioactive isotope sample to decay. |
| radioactive dating | The process of determining the age of an object using the half-life of one or more radioactive isotopes. |
| tracer | A radioactive isotope that can be followed through the steps of a chemical reaction or industrial process. |
| radiation therapy | A process in which radioactive elements are used to destroy unhealthy cells. |
| matter | Anything that has mass and takes up space. |
| physical change | A change that alters the form or appearance of a substance but does not make the material into another substance. |
| chemical change | A change in matter that produces new substances. |
| Law of conservation of matter | Matter cannot be created or destroyed, it can only change form. The total mass will remain the same. |
| Law of conservation of energy | Energy cannot be created or destroyed, it can only change form. |
| chemical equation | A short, easy way to show a chemical reaction, using symbols instead of words. |
| chemical formula | A representation of a substance using symbols for its elements. |
| reactant | A substance that enters into a chemical reaction, written on the left of the arrow. |
| arrow | Indicates a change to a new substance in a chemical reaction. |
| chemical reaction | A process in which one or more substances, the reactants, are converted to one or more different substances, the products. |
| exothermic | Energy in a chemical reaction is released. |
| endothermic | Energy in a chemical reaction is absorbed. |
| nuclear energy | Energy stored in the nucleus of an atom. |
| fusion | Joining the nuclei together. |
| fission | Splitting nuclei. |
| product | Written on the right of a chemical reaction. |
| balanced equation | An equation for a chemical reaction in which the number of atoms for each element in the reaction and the total charge are equal on both sides of the equation. |
