atomic history webquest

Who presented “dalton’s atomic theory”
john Dalton
name the five postulates of the atomic theory.
1. all matter is composed of extremely small particles called atoms
2.all atoms of a given element are identical (same size,mass, and chemical properties). Atoms of a specific element are different from those of any other element
3.atoms cannot be created, divided, into smaller pieces, or destroyed
4. Different atoms combine in simple whole number ratios to form compounds
5. In chemical reaction, atoms are separated, combined, or rearranged
Law of conservation of mass
matter is not created nor destroyed
law of definite proportions
compound always has the same elements, in the same proportions
law of multiple proportions
elements can combine in different proportions but when they do the compounds will have different properties
how did dalton imagine an atom
as a solid sphere
What did JJ Thompson’s experiments consist of ?
with a cathode ray tube which showed that there were smaller particles than the atom.
Who performed a famous experiment in 1909?
Robert Millikan
What experiment did Millikan preform?
he preformed the oil drop experiment which determined the charge of an electron. Since atoms were known to be neutral. Thomson reasoned there must be some positive charge in the atom, too.
Plum-pudding model
electrons of an atoms are dispersed throughout the positively charged cloud
solid sphere model
plum-pudding model
look on sheet
empty space model
James Chadwick in 1932 detected
the neutron
Ernest Rutherford preformed what experiment ?
gold-foil
What did the experiment consist of ?
he shot alpha particles at a thin piece of gold foil. If the atom contained no other particles besides electrons, the alpha particles should pass straight through the gold foil and about 1 to 2000 bounced back at him
What was the result of other experiment by Rutherford and Thomson
naming of the proton
shows the number of protons increases by one as you went from element to element on the periodic table
atomic number
number of protons in an atom

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