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Chapter Two Chem

Atoms and Radioactivity

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.
Created by: JessicaThompson