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Chapter Two Chem
Atoms and Radioactivity
Question | Answer |
---|---|
Alpha particle | A form of nuclear radiation consisting of two protons and two neutrons (A helium nucleus). |
Atomic Mass | Weighted average mass of all the naturally occurring isotopes of an atom. |
Atomic Number | Located above the symbol of the element on the periodic table. Equal to the number of protons in an element. |
Avogardo's Number | Number of particles present in a mole of a substance. 6.02 * 10 ^23 |
Beta particle | Form of nuclear radiation where an unstable neutron emits a high-energy electron, the beta particle, changing the neuron into a proton. |
Curie (Ci) | Unit of radiation equal to 3.7 * 10^10 disintegration per second. |
Electron | Negatively charged subatomic particle. |
Gamma Ray | High-energy nuclear radiation emitted to stabilize a radioactive nucleus. |
Half-life | Amount of time it takes for one-half of the atoms in a radioactive sample to decay. |
Ionizing radiation | General name for high-energy radiation of any kind (nuclear, X-ray |
Isotope | Atoms that have the same number of protons but different numbers of neutrons. |
Mass number | Total number of protons and neutrons in an atom. |
Molar mass | The mass in grams of 1 mole of a substance. For an element this is numerically equivalent to atomic mass. |
Mole | A mole relates to the mass of an element or elements in grams to the number of particles it contains. It is 6.02 * 10^23 atoms, molecules, or other particles. |
Nuclear decay equation | A chemical equation where the reactant is a radioactive isotope and the products are a radioactive particle and a second radioisotope. |
Nuclear radiation | Energy emitted spontaneously from the nucleus of an atom. |
Neutron | No charge. Found in nucleus. |
Radioactive | Elements that spontaneously emit nuclear radiation. |
Radioactive decay | Process of a nucleus spontaneously emitting radiation. |
radioisotope | Radioactive isotope of an element. |
Tracer | A minimum amount of radioactive substance used for detection only. |
Valence electrons | Electrons found in the highest occupied energy level |
Valence shell | The highest occupied energy level of an atom containing electrons. |