The Early Days of Lore (How the Atom Began) Flashcard

law of conservation of matter
states that matter cannot be created or destroyed
Antoine Lavoisier
French tax collector who was decapitated during the French Revolution and came up with the law of conservation of matter
law of definite proportions
states that elements in a compound always occur by mass in same ratios
John Dalton
English-Quaker, unmarried, schoolteacher whose hobby was studying the weather, lived in the country and developed the atomic theory
law of constant composition
states that compositions of compounds is constant based on number of atoms
J.J. Thomson
discovered the electron
Cathode Ray Tube Experiment
experiment in which Thomson filled a cathode ray tube with gas and plugged it into a battery. When he put a magnet at the top of tube, the gas would moved downward.
plum pudding model of the atom
model showing that negative electrons were spread evenly throughout the positive charge of the rest of the atom
beta particle
another name for an electron
electron
an extremely tiny, negatively charged particle
proton
a positively charged particle located in the nucleus
neutron
a particle with no charge, located in the nucleus
Becquerel
discovered radioactivity. Had ore with uranium in it. He stuck it in a drawer on top of a photographic film and a key and locks it. Key is imprinted on film.
Pierre Curie
Polish scientist who marries a brilliant woman. He dies in an accident.
Marie Curie
born in Poland. Sent to Paris to go to school for science. Gets master’s degree and ends up in Becquerel’s lab. Discovered that atoms can change. Two elements were named after this person.
Curiam and Polonium
these two elements were named after Marie Curie.
alpha particle
this had 2 neutrons/2 protons/no electrons. it had a positive charge and a helium nucleus.
gamma particle
this had high energy and invisible light.
4He2
symbol for alpha particle
Ernest Rutherford
famous for his gold foil experiment in which he discovered the nucleus
nucleus
the center of an atom in which protons and neutrons are located; small, dense, contains all mass, positive charge
Hans Geiger
Ernest Rutherford’s lab assistant
Gold Foil Experiment
experiment performed by Rutherford which demonstrated the fact that there is a nucleus
mass of element/mass of compound x 100=% composition
the formula for percent composition
Robert Millikan
American who discovered the charge on an electron. Had the oil drop experiment.
nuclear force
force that allows protons & neutrons to be close together
Z
symbol for atomic number
isotopes
different varieties of atoms of the same elements
mass number
number of protons + number of neutrons
examples of isotopes
C-12, C-13, C-14: what are these examples of?

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