Early Atomic Theory Flashcards
Who proposed that all matter is composed of indivisible elements?
Democritus and Leucippus
Who developed the Law of Mass Conservation?
Antoine Lavoisier
What was Lavoiser’s experiment?
The bell jars with shiny tin that turned into flakey powder; retained same mass
Who contributed to the Law of Constant Composition?
Joseph Proust
What is the Law of Constant Composition?
All samples of a specific compound have the same composition of elements by mass
What is the Law of Mass Conservation?
the total mass of a substance remains the same before and after a chemical reaction; matter not created/destroyed
Who is given credit for Atomic Theory?
John Dalton
What is Atomic Theory?
- elements composed of microscopic indivisible spheres
- All elements of the same type are identical
- Atoms combine in simple whole number atios. (The law of constant composition)
- The numbers and kinds of elements in a given compound are constant
- Atoms are neither created nor destroyed (The law of conservation of mass)
What is the Law of Multiple Proportions?
Two elements may form more than one compound with the ratio of elements in both compounds being small whole numbers
Who used the cathode ray tube (CRT) and discovered the atom wasn’t as simple as previously believed?
JJ Thomson
What model did JJ Thomson use?
Plum pudding; pos. pudding neg. plums
Who determined the charge (and mass) of an electron through the oil drop experiment?
Robert Millikan
Who developed the Nuclear Model of the Atom?
Ernest Rutherford and Hans Geiger
Who discovered the neutron with alpha particles?
James Chadwick
Why did Rutherford and Geiger use gold foil for their experiment?
- Gold is malleable
- Gold has a lot of protons
