Where it all is
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John Newlands determined a repeating
pattern of every 8 elements. He called it the
law of octaves.
Developed in the 1860’s
Dmitri Mendeleev arranged the first on based
on Atomic Masses.
Henry Moseley Arranged the Modern Periodic
Table based on Atomic Number.
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Based on increasing atomic number and on
electron configurations
◦ Results in repeating chemical and physical
properties.
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Groups or Families
◦ Columns that go up and down.
◦ There are 18 Groups
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Periods
◦ Rows that go across
◦ There are 7 Periods
Metals
◦ On the left side
◦ Make up ¾ of all elements
◦ Malleable, Ductile, Conduct electricity, form positive
ions.
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NonMetals
◦ On the Right side
◦ Dull, Brittle, Insulators, form negative ions
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Metalloids (Semimetals)
◦ Found along the staircase between metals and
nonmetals, have properties of both.
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Highly reactive
Replace Hydrogen in Water
All have 1 valence electron
All are s1
Forms +1 ions
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Very reactive
Don’t replace Hydrogen in Water
◦ Readily burn in O2 when exposed to heat
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Calcium makes up your bones.
Batteries get their name from this group
Have 2 Valence electrons
◦ All are s2 – forms +2 ions
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These are the common metals
All have d orbitals filling
Less reactive then other metals
Copper, Silver, and Gold least reactive
Forms various positive ions
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Have 3 Valence electrons
◦ All are s2 p1
◦ All form +3 ions except
 Boron which forms a –3 ion
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One is a metalloid (Boron)
The rest are all metals
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Carbon family has 4 valence electrons
 All are s2 p2
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Composed of:
◦ one non-metal (Carbon)
◦ Two metaloids (Silicon and Germanium
◦ Two metals (Tin and Lead)
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Carbon always forms 4 bonds
◦ All known life based on Carbon
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Computers function based on Silicon and
Germanium’s unique properties
◦ They conduct electricity but not heat
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Lead and Tin are common metals
◦ Used to be used a lot in food storage
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All have 5 valence electrons
◦ All are s2 p3
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Composed of:
◦ two nonmetals - Nitrogen and Phosphorous
◦ Two metalloids – Arsenic and Antimony
◦ One metal - Bismuth
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Nitrogen:
◦ makes up most of the atmosphere
◦ Critical to plant and animal life
◦ Forms strong bonds that are used in explosives
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Phosphorous
◦ Critical to plant and animal life
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All have 6 valence electrons
◦ All are s2 p4
◦ Usually form 2 bonds
 Form – 2 ions (except Polonium +2, +4 ions)
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Composed of:
◦ 3 nonmetals – Oxygen, Sulfur, Selenium
◦ 1 metalloid – Tellerium
◦ 1 metal - Polonium
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All have 7 valence electrons
◦ All are s2 p5
◦ Forms 1 bond
 Forms – 1 ions
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All are nonmetals
Highly reactive
◦ Never found in nature as single atoms
◦ When pure will form F2, Cl2, Br2, I2
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All have 8 valence electrons
◦ All are s2 p6
◦ Rarely form bonds
 Never form ions
◦ Helium, Neon, Argon have never been found in a
compound
◦ Krypton, Xenon, Radium can sometimes be forced
to form compounds – but these are very unstable
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Called Rare Earths
◦ They are rare on earth - Most are manmade
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All are radioactive
All elements greater then Uranium (92) are
manmade
Some are used in medical research
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Atomic Radius – The size of the atom.
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Hard to measure due to cloud not being distinct
Smaller Up and Right
Negative Ions Larger
Positive Ions Smaller
Ionization Energy – The energy required to
remove one electron, the more electrons
removed, the more energy required.
◦ Greater Up and Right
◦ Fluorine the highest
◦ Francium the lowest
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Electronegativity – The ability of atoms to
attract electrons during bonding
◦ Greater Up and Right
◦ Fluorine the Greatest Electronegivity
◦ Francium the Lowest
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Octet Rule – Atoms Tend to gain, lose or
share electrons to have a full (s2, p6) valence
shell.
Shielding Effect – The ability of inner
electrons to shield valence electrons from the
nucleus. Increase Down, Across Same