Chemistry Test 2008 Atoms/Scientists

the study of properties and interactions of matter

an explanation based on repeated tests and observations

observable fact of nature

-440 B.C.
-believed that the atom was the smallest building block
-atomos=building blocks

-350 B.C.
-4 elements=earth, wind, fire, water
-tutored Alexander the Great
-Philosopher-believed the power of mind explains everything

-more than 4 elements and they got together in different proportions
-Discovered different "pure" substances (not mixed with something else)
-known as wizards
-made potions
-H2O=water=2 hydrogen atoms + 1 oxygen atom

change of one element into another element

-1803
-building blocks of atoms (billiard balls)
-Father of Modern Chemistry
-Quaker School teacher
-Found that each element is a different kind of "building block"
-used the word atoms
-atoms combine in a certain ratio to make new things
-atoms of the same element are the same
-atoms of different elements are different

-1897
-Plum Pudding Model (jello w/ fruit chunks)
-experimented with cathode ray tube
-decided atoms actually have TWO parts (mostly positive w/ little negative chunks)
-atoms are not solid
-found out that when he shot a beam through a CRT, the beam curved when he put a charge on the plates
-atoms are not neutral

-1909
-shot radiation to discover that an atom is mostly open space
-shot radium at gold (dense & thin)
-particles bounced off backwards (he thought it would go through)
-atoms are mostly open space

-energy level model
-improved Thomson & Rutherford's model but not orderly pairs
-they are all over the place (paths)

electron cloud model

discovered neutrons- used weight as a clue

smaller quarks

smaller leptons