Atom History

Question 1

Law of Definite Proportions

Answer 1

in a chemical substance, the elements are always combined in the same proportions by mass
-ex: a + bbb = cccc

Question 2

Law of Multiple Proportions

Answer 2

when two elements react to form more than one substance, the different masses of one element that are combined with the same mass of the other element are in a ratio of small whole numbers

Question 3

Dalton’s Atomic Theory

Answer 3

-matter is made of tiny particles called atoms
-atoms are indivisible (INCORRECT)
-during a chemical reaction, atoms are
rearranged, but they do not break apart,
nor are they created or destroyed
-the atoms of different elements differ in
mass and other properties
-atoms of one element can combine with
atoms of another element to form
compounds

Question 4

compounds

Answer 4

New, complex entities. Atoms of one element are combined with atoms of another element to create a compound.

Question 5

J.J. Thomson’s Cathode Ray Experiment

Answer 5

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Question 6

Rutherford’s Gold Foil Experiment

Answer 6

Alpha particles were fired at a thin sheet of gold, and some went straight through, but some bounced right back. Results showed that the positive charge was concentrated in the center of the atom (the nucleus). The alpha particles passed straight through the positive nucleus, except the ones that hit something else and bounced back.

Question 7

Nuclear Fission

Answer 7

the process of splitting an atom

Question 8

alpha particle

Answer 8

a large, positively charged particle