Notes

AlphaRadiation ionizing radiation consisting of alpha particles, emitted by some substances undergoing radioactive decay
AlphaScatteringExperiment the scattering of an alpha particle through a large angle with respect to the original direction of motion of the particle
AtomicTheoryofMatter all material substances are composed of minute particles or atoms of a comparatively small number of kinds and all the atoms of the same kind are uniform in size, weight, and other properties
AtomicMassUnit a unit of mass used to express atomic and molecular weights, equal to one-twelfth of the mass of an atom of carbon-12
AtomicNumber he number of protons in the nucleus of an atom
Atomos a Greek word meaning uncuttable
Becquerel the SI derived unit of radioactivity
BetaRadiation High-energy electrons, carrying a negative charge
CathodeRay a beam of electrons emitted from the cathode of a high-vacuum tube
CathodeRayTube a high-vacuum tube in which cathode rays produce a luminous image on a fluorescent screen
MarieCurie chemist who conducted pioneering research on radioactivity
PierreCurie a pioneer in crystallography, magnetism, piezoelectricity and radioactivity
JohnDalton known for his pioneering work in the development of modern atomic theory
Democritus remembered today for his formulation of an atomic theory of the universe
Deuterium a stable isotope of hydrogen with a mass approximately twice that of the usual isotope.
Electron a stable subatomic particle with a charge of negative electricity
MichaelFaraday English scientist who contributed to the fields of electromagnetism and electrochemistry
BenjaminFranklin one of the Founding Fathers of the United States.
GammaRadiations known as gamma rays
Ion an atom or molecule with a net electric charge due to the loss or gain of one or more electrons
Isotope each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei
AntoineLavoisier French nobleman and chemist central to the 18th-century chemical revolution
LawOfConservationOfMatter states matter cannot be made or destroyed
LawOfConstantComposition states that all samples of a given chemical compound have the same elemental composition by mass
MassNumber the total number of protons and neutrons in a nucleus
RobertMillikan experimental physicist honored with a Nobel Prize for Physics
HenryMoseley justification from physical laws of the previous empirical and chemical concept of the atomic number
NagativeIon group of atoms formed by the loss or gain of one or more electrons
Neutron subatomic particle of about the same mass as a proton but with no electric charge
Nucleus positively charged central core of an atom
OilDroppletExperiment experiment to measure the elementary electric charge
PlumPuddingModel atomic structure proposed by J.J. Thomson
PositiveIon electrically charged atom or group of atoms formed by the loss or gain of one or more electrons
Proton stable particle with a positive electric charge
Proust discovery of the law of constant composition
RadioactiveDecay transformation of an unstable atomic nucleus into a lighter one
Radioactivity emitting or relating to the emission of ionizing radiation or particles
ErnestRutherford British physicist who became known as the father of nuclear physics
StrongNuclearForce is one of the four basic forces in nature
ThinGoldFoil Ernest Rutherford shot a beam of alpha particles at a sheet of gold foil, a few of the particles were deflected
JJThomson appointed to the Cavendish Professorship of Experimental Physics
Tritium a radioactive isotope of hydrogen with a mass approximately three times that of the common