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19 Cards in this Set

  • Front
  • Back
smallest particle of an element that retains the chemical identity of the element
natural law describing the fact that a given compound always contains the same element in the same proportions
law of constant composition
theory proposed by john dalton stating that elements are composed of atoms, all atoms of a given element are identical but different from atoms of other elements, atoms are neither created nor destroyed in a chemical reaction, and a given compound always has the same relative numbers and kinds of atoms
atomic theory of matter
stream of electrons emitted by a negatively charged electrode and attracted by a positively charged electrode
cathode ray
evacuated glass tube in which a stream of electrons emitted by a cathode strikes a fluorescent material, causing it to glow
cathode ray tube
negatively charged particle within an atom
spontaneous emission of radiation from an atom
concentrated core of an atom, which contains protons and neutrons
positively charged particle within the nucleus of an aton
neutral particle within the nucleus of an atom
unit by which the mass of an atom or atomic particle is expressed
atomic mass unit
number of protons in the nucleus of an atom
atomic number
atom or group of atoms that has a positive or negative charge because it has gained or lost electrons
atom that has the same of protons as another atom, but has a different number of neutrons
sum of the number of protons and neutrons in the nucleus of a given atom
mass number
weighed average of the masses of the existing isotopes of an element
atomic mass
the process that changed the composition of an atom
nuclear reaction
attractive force among the particles in the nucleus of an atom
strong nuclear force
spontaneous breakdown of an unstable atomic nucleus, durin which alpha particles, beta particles, and gamma rays may be entered
radioactive decay