Download the # protons is not equal to the # neutrons

MATTER
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Atomic Structure
The Atom
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Continuous Theory of Matter
Early Greeks
Matter could be divided into smaller
and smaller bits and still have the
same properties.
Discontinuous Theory of Matter
Democritus and Leucippus
Matter can only be divided so small and
still have the same properties.
“Atomos” meaning indivisible
Followers “atomists”
John Dalton’s Theory of the Atom
•All matter is composed of atoms which are
indivisible.
•All atoms of the same element are exactly
alike.
•Atoms of different elements are different.
•Compounds are formed by joining 2 or more
elements in a definite whole-number ratio.
J.J. Thomson’s Atomic Model
“Plum Pudding Model”
Knew the atom was neutral
Knew there were negative particles
Inferred that there had to be positive particles
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Rutherford's Gold Foil Experiment
Rutherford’s Gold Foil Experiment
.fsu.edu/ http://micro.magnet electromag/java/rutherford/
Ernest Rutherford’s Atomic Model
The nucleus was a small dense center of
the atom
Most of the atom was made up of empty
space
Neil’s Bohr’s Atomic Model
Protons and neutrons are in the small
positively charged nucleus.
Electrons are found in orbits or shells
outside the nucleus
Subatomic Particles
location
charge
Mass
Proton
Nucleus
Positive
1 AMU
Neutron
nucleus
neutral
1 AMU
electron
Outside
nucleus
negative
1/2000
AMU
Isotopes- atoms of the same element
which have a different mass due to a
different number of neutrons.
Ex. C-12
C-14
#p = 6
#p = 6
#e- = 6
# e- = 6
#n = 6
#n=8
Isotopes will behave chemically the same
because how they react depends upon their
number of valence electrons. The difference
is in how stable the nucleus is. The general
rule is that the isotope will be radioactive if
the # protons is not equal to the # neutrons.
Which is most likely radioactive?
C-12
or
C-14
Because of all these scientists, we enjoy ..,