Unit 4 The Periodic Table

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Unit 5 Periodic Trends Part 2
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Trends of the Periodic Table

• Atomic Number
• Atomic Mass
• Metal / Nonmetal Trend
• Atomic Radius
• Ionization Energy
• Electronegativity

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Atomic Number

• The number of protons in one atom of a given
  element.
• Increases as you move down a group.
• Increases as you move across a period.

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Atomic Number/Avg.Atomic Mass
increases
I n c r e a s e s
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Average Atomic Mass

• The average mass of all the isotopes of a given
  element.
• Increases as you move down a group.
• Increases as you move across a period.

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Metal / Nonmetal / Metalloid

• Elements on the left side of the table are
  metals.
• There are 88 metals on the periodic table.

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Discovery VideoChemical Properties of Metals
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Metal / Nonmetal / Metalloid

• Elements on the right side are nonmetals.
• There are 17 nonmetals on the periodic table.

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Discovery VideoChemical Properties of NonMetals
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Metal / Nonmetal / Metalloid

• Elements on the staircase between the metals
  and nonmetals are metalloids.
• There are 7 metalloids on the periodic table

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Stair Step Line
Separates metals from non metals metalloids
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Properties of Metalloids

• Metalloids have properties of both metals and
  nonmetals.
• For example Silicon
• Is silver, shiny and a conductor like a metal.
• Is rough, brittle and has no rxn to acid like a
  nonmetal.

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Properties of Metals and Nonmetals
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Most Active Nonmetal
Most Active Metal
Metalloids
Metals
Nonmetals
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Discovery VideoMetals vs non metals
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Activity Series

• Some metals are more reactive than others
• and will replace less reactive metals during
• a reaction.
• Li, K, Ca, Na, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag
• DECREASING REACTIVITY ? ? ? ? ? ?
• Will Ca replace Zn in a reaction?
• Yes, Ca is more reactive than Zn
• Will Zn replace Mg in a reaction?
• No, Zn is less reactive than Mg

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Atomic Radius

• The distance from the center of an atoms nucleus
  to its outermost electron.
• Atomic radius increases as you move down a group
  on the periodic table.
• Because electron clouds are added.
• Atomic radius decreases as you move across a
  period on the periodic table.
• Full shells with paired-up electrons have less
  repulsion, so the take up less space.

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Atomic Radius the fallen snowman
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Ionization Energy

• The amount of energy required to remove a valence
  e- from an atom.
• Decreases as you move down a group on the
  periodic table.
• More shielding from full electron shells.
• Increases as you move across a period on the
  periodic table.
• More difficult to remove electrons from a full
  shell.

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Electronegativity

• The attraction for shared electrons in a chemical
  bond.
• Decreases as you move down a group on the
  periodic table.
• Valence electrons get farther from the nucleus
  because there are more full e- shells. The
  attraction between the nucleus and electrons
  decreases.
• Increases as you move across a period on the
  periodic table.
• More protons, stronger attraction to electrons.

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Electronegativity/Ionization Energy

• Look at the positions of Fluorine and Francium on
  the periodic table.
• Francium doesnt need another electron to become
  stable. It actually would be more stable by
  giving one away. (Has lowest ionization energy
  due to 6 full shells of shielding.)

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Electronegativity/Ionization Energy

• Fluorine needs one more electron to fill its
  valence shell.
• It has the strongest electronegativity. The
  closer the valence electrons are to the nucleus,
  the stronger the electronegativity. (The valence
  e- are closer to the positive nucleus.)

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Ionization Energy Electronegativity

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Discovery VideoBrief Review of Periodic Table
Groups Periods