Atoms, Elements, and the Periodic Table

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Atoms, Elements, and the Periodic Table
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Online Periodic Tables

• If you need to use a periodic table while at
  home, try these
• http//www.chemicool.com/
• http//periodic.lanl.gov/default.htm
• NC DPI (official one for Science EOG)
• http//www.ncpublicschools.org/docs/accountability
  /testing/eog/science/2009grade8periodic.pdf

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PART 1 ATOMS

• What are atoms made of?
• NUCLEUS center of the atom
• PROTON ()
• NEUTRON (0)
• ELECTRON (-) surrounds the atom in a cloud.

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An Atom DONT DRAW THIS ONE
NUCLEUS
ELECTRONS
PROTON
NEUTRON
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An Atom DRAW THIS ONE
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PROTONS

• Positively charged particle
• Found in nucleus of an atom
• Same as the atomic
• Tells what kind of atom it is, the specific
  element. For example hydrogen, oxygen, sodium,
  gold

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NEUTRONS

• Neutrally charged particle (no charge)
• Found in nucleus of an atom
• Tells what version (isotope) of the element it is

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ELECTRONS

• Negatively charged particle
• Found outside of the nucleus
• They surround the nucleus in a cloud because we
  dont know exactly where they are at any given
  time
• Much smaller than protons and neutrons
• Usually equal to the protons

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Most of the atom is taken up by the space
between the nucleus and the electrons.
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ELEMENTS

• ELEMENT A specific kind of atom. Determined by
  the number of protons (atomic )
• ATOM generic (car)
• ELEMENT specific (Porsche 911 or Ford Edge etc)
• Every atom of an element has the same number of
  protons. For example every Lithium atom always
  has 3 protons

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• ATOMIC NUMBER the number of protons in an atom.
  This tells you what kind of element it is.
• ISOTOPE Atoms with the same number of protons
  and a different number of neutrons.
• MASS NUMBER The sum of the protons and neutrons
  in an atom. This is how you identify the
  isotopes.
• ATOMIC MASS the average mass of all the
  isotopes of an element

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DIFFERENT ISOTOPES OF CARBON
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• Dmitri Mendeleev was the first person to organize
  the elements. He made the first periodic table.
• He organized it in order of increasing atomic
  mass. We dont do it this way any more.
• CHEMICAL SYMBOL a short way of telling what the
  chemical is. Its usually 1 or 2 letters.
  EXAMPLES
• Barium Ba
• Tungsten W

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• ATOMIC MASS the average mass of an element.
  This includes all the isotopes of that element.

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• The elements in todays Periodic Table are
  arranged by their atomic number.
• A PERIOD a horizontal row in the periodic
  table. There are 7 of them.
• Elements in a period change from left to right
  according to a pattern. There is a trend that
  the elements follow.

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PERIOD HORIZONTAL
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• A GROUP A vertical column on the periodic
  table. Also called a FAMILY. There are 18 of
  them.
• Elements in a group all have similar
  characteristics. Groups are often named for the
  top element in the column. EXAMPLE
• Carbon group
• Nitrogen family

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GROUP or FAMILY VERTICAL
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12 Mg Magnesium 24.305
ATOMIC NUMBER
CHEMICAL SYMBOL
CHEMICAL NAME
ATOMIC MASS
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of Protons of Electrons of Neutrons
Atomic Number Mass Element Name
Group Period