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Chapter 04 -History

Terms in this set (71)

● All matter is composed of ____.
atoms
● An ____is the smallest particle of an element that retains its identity in a __ __.
Atom, Chemical Reaction
● Philosophers and scientists began proposing theories on the structures of atoms ___________________________________
despite their inability to see and observe them.
Who was Greek philosopher in 400 BC?
Democritus
He was the first to suggest the existence of an atom?
Democritus
Democritus believed the world to be made up of what two things?
empty space and tiny particles called atoms
Democritus reasoned that atoms were ____ and ____.
indestructible, uncuttable.
Democritus did not explain ___ ___.
chemical behavior
Democritus lacked ___ ___.
experimental evidence
Who was Greek philosopher in 300 BC?
Aristotle
Who was Student of Plato and teacher of Alexander the Great?
Aristotle
Who was know as the MASTER OF THOSE WHO KNOW?
Aristotle
What does IPSE DIXIT mean?
He himself said it
Who established the world greatest library at Alexandria?
Aristotle
Who established the Science of Biology?
Aristotle
Who Supported the Four Element Hypothesis?
Aristotle
Wha is the Four Element Hypothesis?
Earth , Water, Air, and Fire
When was Supported the Four Element Hypothesis Suggested?
450 BC
Who is the Father of modern chemistry?
John Dalton
John Dalton was a ___, ___, and __.
Chemist, Physicist, and Meteorologist
● Who was English chemist who began the modern process of discovery regarding atoms?
John Dalton
Who Used experimental methods to transform Democritus's ideas on atoms into 4 scientific theories?
John Dalton
What is Dalton's First Atomic Theory?
● All elements are composed of tiny indivisible particles called atoms.
What is Dalton's Second Atomic Theory?
● Atoms of the same element are identical. The atoms of any one element are different from those of any other element.
What is Dalton's Third Atomic Theory?
● Atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios to form compounds.
What is Dalton's Fourth Atomic Theory?
● Chemical reactions occur when atoms are separated from each other, joined, or rearranged in a different combination. Atoms of one element, however, are never changed into atoms of another element as a result of a chemical reaction.
What is Dalton's concepts of Mercury and Copper?
Page 103 in Textbook
John Dalton's Theories are eventually know to be ___.
divisible
John Dalton's Atomic Theory can break down into ___ ___.
subatomic particles.
● John Dalton had three kinds of subatomic particles are ____ , ____ , and ____ .
electrons, protons, and neutrons
What is the actual mass of the electron?
9.11 x 10 up-28
What is the actual mass of the proton?
1.67 x 10 up-24
What is the actual mass of the neutron?
1.67 x 10 up-24
What is the charge of the neutron?
neutral
What is the charge of the proton?
positive
What is the charge of the electron?
negative
Who was English physicist, discovered the electron?
J.J. Thomson
Electron was the 1st subatomic particle to be discovered in ___.
1897
Who found the Electrons are negatively charged subatomic particles?
J.J. Thomson
JJ Thomson did experiments that passed electric currents through gases at ___ ____ .
low pressure.
J.J. Thomson created an experiment in which the gases were in glass tubes with metal disks (_____ ) at the ends. The ___ were connected to a source of electricity
electrodes
J.J. Thomson discovered the one electrode (____ ) became positively charged. The other (____ ) became negatively charged.
anode, cathode
J.J. Thomson concluded that the result was a cathode ray, a glowing beam that traveled from the ____________. The negative side sends a stream of electrons.
cathode to the anode
J.J. Thomson found that a cathode ray is deflected by electrically charged ____ ____.
metal plates
J.J. Thomson found that the positively charged plate attracts the ___ ___, while a negatively charged plate ___ ___.
cathode ray, repels it.
J.J. Thomson used magnetic plates to change the ray's direction to a ____ ____.
positive end
What did J.J. Thomson hypothesize about the a cathode ray tube?
That is a stream of tiny negatively charged particles moving at high speed. These were later named electrons.
J.J. Thomson also discovered that cathode ray can also be deflected by a ____.
magnet.
Robert Millikan won the noble prize in __.
1923
Robert Millikan won the noble prize for ___
measurement of the electric charge.
Robert Millikan was a __
physicist
What is Millikan's oil drop experiement?
Used an oil drop experiment by suspending negative charged oil droplets between two charged plates and he calculated the mass of the electron. His numbers are widely accepted today
How do Electric charges exist?
in whole-number multiples of a single basic unit; that is, there are no fractions of charges.
When did Eugen Goldstein observed a cathode-ray tube?
1886
What did Eugen Goldstein observe?
observed a cathode-ray tube with rays traveling in the direction opposite to cathode rays. He concluded they were made of positive particles called protons.
Who has his image on a $100 bill in New Zealand?
Rutherford
Eugen Goldstein was a __
German physicist
James Chadwick discovered the neutron in ?
1932
James Chadwick won the noble prize in __.
1935
What did James Chadwick discover?
neutron, a subatomic particle with no charge but with a mass nearly equal to that of a proton.
What is the plum-pudding model?
Discovery of the electron - they were evenly distributed throughout an atom filled uniformly with positive charged materials. He visualized it as a plum-budding model
Who coined the plum-pudding model?
J.J. Thompson
What did Earnest Rutherford do in 1911?
determine the structure of an atom.
Who won noble prize in 1908?
Earnest Rutherford
Rutherford used a lead box; he directed a beam of ____ particles (___ atoms with a double positive charge) at a sheet of ___ foil.
alpha, helium, gold
Rutherford predicted two things would happen.
the beam was expected to easily pass through the sheet and He predicted some would sightly bounce off.
What did Rutherford did not figure to happen?
particles bounced off the sheet at sharp angles.
Explain the comment.
"IT WAS QUITE THE MOST INCREDIBLE EVENT THAT HAS EVER HAPPENED TO ME IN MY LIFE. IT WAS ALMOST AS INCREDIBLE AS IF YOU FIRED A 15 INCH SHELL AT A PIECE OF PAPER AND IT CAME BACK AND HIT YOU"
● These results led him to conclude that an atom has mostly empty space (easy to pass through) except for a small region where most of the mass and positive charge is concentrated (great deflection).
Rutherford concluded that the nuclear atom model has
the nucleus is tiny and densely packed compared with the atom as a whole.
Rutherford has concluded that Atoms have positively charged protons and neutral neutrons ____ a nucleus, and negatively charged electrons ____ the nucleus.
inside, outside
What are an Isotopes?
are atoms that have the same number of protons but different numbers of neutrons
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