Atoms

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Atoms
Atoms are the building blocks of elements. They
are made up of three subatomic particles 1)
protons are found in the nucleus and have a
positive charge. 2) neutrons are also
found in the nucleus, but have no
charge. 3) electrons orbit around the nucleus
and have a negative
charge.
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• Electrons can jump through space and change the
  charge on an atom.
• When the number of electrons equals the number of
  protons the atom will have no charge.

electrons
protons
p
p
neutrons
p
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• When the number of electrons is greater than the
  number of protons the atom will have a negative
  charge.

electrons
protons
p
p
neutrons
p
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• When the number of electrons is less than the
  number of protons the atom will have a positive
  charge.

electrons
protons
p
neutrons
p
p
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Dalton's Atomic Theory
John Dalton (1766-1844) was an English chemist,
meteorologist, and physicist. He is best known
for his pioneering work in the development of the
modern atomic theory.
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1. All matter is made up of small particles called
   atoms.

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2) Atoms of one type of element are identical to
each other, but are different from atoms of
other elements.
Sodium Atom
Silver Atom
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3) Atoms cannot be created nor destroyed by
ordinary means.
Not By
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4) Atoms may combine with other atoms to form
larger particles called molecules.
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Why is this important?
Nuclear Energy is energy from atoms
Nuclear energy is energy in the nucleus (core) of
an atom. There is enormous energy in the bonds
that hold atoms together.
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Nuclear energy can be used to make electricity.
But first the energy must be released. It can be
released from atoms in two ways nuclear fission
or nuclear fusion.
In nuclear fission, atoms are split apart to form
smaller atoms, releasing energy!
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How many protons, neutrons, and electrons are
there in an atom?
The number of protons in an atom is called the
atomic number.
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The number of protons and electrons in an atom is
the same.
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Finally, we have the mass number (atomic mass).
The mass number represents the sum of protons and
neutrons in an atom.
Number of neutrons mass number atomic number