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Antoine Lavoisier
Law of Conservation of mass: when a chemical change occurs, the mass at the beginning of the chemical change was equal to the mass at the end of the chemical change. -
Proust
Law of definite proportions: specific substances always contain elements in the same ration by mass -
Gay-Lussac
The Law of combining volumes stated that when two gases react, the volumes of the reactants and products—if gases—are in whole number ratios. -
Dalton
He stated that The ratio of masses of one element that combine with a constant mass of another element can be expressed in small whole numbers. -
Avogadro
He proposed that equal volumes of gases, at the same temperature and pressure, contain equal numbers of molecules. -
Marie Curie
Marie Curie, with the help of her husband found that rays are given off by uranium and radium and discovered radium and polonium. -
Henri Becquerel
He discovered uranium radiation and lead Marie Curie to her discovery. -
J.J. Thomson
He discovered that cathode rays consist of electrons and determined the ratio of an electron’s charge to its mass. -
Albert Einstein
Einstein explained the origin of of the energy released during nuclear changes.
-E=mc2 : mass and energy are equivalent -
Max Planck
He stated that energy is given off in quanta (little packets) instead of instead of continuously
-E= hv (h is constant)
-The quantum theory -
Robert Millikan
He made the first accurate measurement of an electron’s charge with the oil drop experiment -
Henry Moseley
Moseley studied X-rays made in X-ray tubes
and found that the wavelength of the x-ray is a characteristic of the metal used as the anode. -
Lord Rutherford
Rutherford brought together group of physicists that developed the beginnings of our concept of atomic structure through experiments and hypothesises under Rutherford’s direction. He and his group concluded that the atom is mostly empty space & small “core” to the atom that contained all the positive charge and most of the mass -
Bohr
Bohr developed a planetary modal of an atom to try to explain the hydrogen spectrum. -
Werner Heisenber
The Heisenberg uncertainty principle shows that it’s impossible to know both the exact position and momentum of an object at the same time.
