Proton
A positively charged atomic particle, nearly 2,000 times more massive than an electron
Neutron
An unstable atomic particle with no electrical charge, slightly heavier than a proton
Electron
An incredibly small, negatively charged atomic particle
Model
A schematic description of a system that accounts for its known properties
Nucleus (of an Atom)
The center of an atom, containing the protons and neutrons
Quantum-Mechanical Model
A complex model used to explain the makeup and motion of atoms
Atomic Number
The number of protons in an atom
Radioactive
The term used to describe an atom that has "too many" or "too few" neutrons
Mass Number
The sum of the numbers of neutrons and protons in the nucleus of an atom
Isotopes
Atoms with the same number of protons but different numbers of neutrons
Element
A collection of atoms that all have the same number of protons
Periodic Table of the Elements
An organized way of grouping elements together
Bohr Orbit
An orbit of an electron in a Bohr Model
Energy Level
Another way of referring to a Bohr Orbit
Electron Shell
Still another way of referring to a Bohr Orbit
Nuclear Force
A force that attracts protons and neutrons to one another in the nucleus
Pion
A particle exchanged by protons and neutrons & have a very short life span
Short-Lived Particle
A particle that exists for a very short time
Radioactivity
An atomic process governed by the weak force
Radioactive Isotope
An atom with a nucleus that is not stable
Beta Decay
Radioactive decay in which a neutron becomes a proton by emitting an electron (a thin sheet of metal for protection)
Daughter Product
The now-stable atom produced by radioactive decay
Alpha Decay
Radioactive Decay in which a radioactive isotope becomes stable by emitting an alpha particle (a sheet of paper for protection)
Alpha Particle
A product of alpha decay that contains two protons and two neutrons (the nucleus of a helium atom)
Gamma Decay
Radioactive Decay in which a radioactive isotope becomes stable by emitting a gamma ray & does not affect the # of neutrons and protons in a radioactive isotope. (requires several inches of lead for protection)
Gamma Ray
A high-energy photon
Half-Life
The time it takes for half of the original sample of a radioactive isotope to decay.
The half-life of C-14 is 5700 years.
Radioactive Dating
A method of measuring the age of objects by using the rate of radioactive decay
Electromagnetic Force/Electroweak Force
holds the electrons in orbit