The Periodic Table

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The Periodic Table

• Chapter 6

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Elements

• Science has come along way since Aristotles
  theory of Air, Water, Fire, and Earth.
• Scientists have identified 90 naturally occurring
  elements, and created about 28 others.

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Elements

• The elements, alone or in combinations, make up
  our bodies, our world, our sun, and in fact, the
  entire universe.

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The most abundant element in the earths crust is
oxygen.
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Why is the Periodic Table important to me?

• The periodic table is the most useful tool to a
  chemist.
• You get to use it on every test.
• It organizes lots of information about all the
  known elements.

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Pre-Periodic Table Chemistry

• was a mess!!!
• No organization of elements.
• Imagine going to a grocery store with no
  organization!!
• Difficult to find information.
• Chemistry didnt make sense.

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Dmitri Mendeleev Father of the Table

• HOW HIS WORKED
• Put elements in rows by increasing average atomic
  mass.
• Put elements in columns by the way they reacted.

• SOME PROBLEMS
• He left blank spaces for what he said were
  undiscovered elements. (Turned out he was
  right!)
• He broke the pattern of increasing atomic mass to
  keep similar reacting elements together.

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The Current Periodic Table

• Mendeleev wasnt too far off.
• Now the elements are put in rows by increasing
  ATOMIC NUMBER!!
• This new organization was created by Henry
  Moseley
• The horizontal rows are called periods and are
  labeled from 1 to 7.
• The vertical columns are called groups are
  labeled from 1 to 18.

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How do we Read the Periodic Table?
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Properties of Metals

• Metals are good conductors of heat and
  electricity.
• Metals are shiny.
• Metals are ductile (can be stretched into thin
  wires).
• Metals are malleable (can be pounded into thin
  sheets).
• A chemical property of metal is its reaction with
  water which results in corrosion.

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Properties of Non-Metals

• Non-metals are poor conductors of heat and
  electricity.
• Non-metals are not ductile or malleable.
• Solid non-metals are brittle and break easily.
• They are dull.
• Many non-metals are gases.

Sulfur
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Properties of Metalloids

• Metalloids (metal-like) have properties of both
  metals and non-metals.
• They are solids that can be shiny or dull.
• They conduct heat and electricity better than
  non-metals but not as well as metals.
• They are ductile and malleable.

Silicon
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GroupsHeres Where the Periodic Table Gets
Useful!!

• Elements in the same group have similar chemical
  and physical properties!!
• (Mendeleev did that on purpose.)

• Why??
• They have the same number of valence electrons.
• They will form the same kinds of ions.

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Families on the Periodic Table

• Columns are also grouped into families.
• Families may be one column, or several columns
  put together.
• Families have names rather than numbers. (Just
  like your family has a common last name.)

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Hydrogen

• Hydrogen belongs to a family of its own.
• Hydrogen is a diatomic, reactive gas.
• Hydrogen was involved in the explosion of the
  Hindenberg.
• Hydrogen is promising as an alternative fuel
  source for automobiles

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Alkali Metals

• 1st column on the periodic table (Group 1) not
  including hydrogen.
• Very reactive metals, always combined with
  something else in nature (like in salt).
• Soft enough to cut with a butter knife

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Alkaline Earth Metals

• Second column on the periodic table. (Group 2)
• Reactive metals that are always combined with
  nonmetals in nature.
• Several of these elements are important mineral
  nutrients (such as Mg and Ca

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Transition Metals

• Elements in groups 3-12
• Less reactive harder metals
• Includes metals used in jewelry and construction.
• Metals used as metal.

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Boron Family

• Elements in group 13
• Aluminum metal was once rare and expensive, not a
  disposable metal.

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Carbon Family

• Elements in group 14
• Contains elements important to life and
  computers.
• Carbon is the basis for an entire branch of
  chemistry.
• Silicon and Germanium are important
  semiconductors.

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Nitrogen Family

• Elements in group 15
• Nitrogen makes up over ¾ of the atmosphere.
• Nitrogen and phosphorus are both important in
  living things.
• Most of the worlds nitrogen is not available to
  living things.
• The red stuff on the tip of matches is phosphorus.

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Oxygen Family or Chalcogens

• Elements in group 16
• Oxygen is necessary for respiration.
• Many things that stink, contain sulfur (rotten
  eggs, garlic, skunks,etc.)

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Halogens

• Elements in group 17
• Very reactive, volatile, diatomic, nonmetals
• Always found combined with other element in
  nature .
• Used as disinfectants and to strengthen teeth.

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The Noble Gases
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The Noble Gases

• Elements in group 18
• VERY unreactive, monatomic gases
• Used in lighted neon signs
• Used in blimps to fix the Hindenberg problem.
• Have a full valence shell.

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Rare Earth Elements

• The thirty rare earth elements are composed of
  the lanthanide and actinide series.
• One element of the lanthanide series and most of
  the elements in the actinide series are called
  trans-uranium, which means synthetic or man-made.

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Periods

• Each horizontal row of elements is called a
  period.
• The elements in a period are not alike in
  properties.
• In fact, the properties change greatly across
  even given row.
• The first element in a period is always an
  extremely active solid. The last element in a
  period, is always an inactive gas.

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Octet Rule

• When atoms of one element react with atoms of
  another there is an adjustment in the outer
  electrons
• (loss, gain, or sharing of these electrons)
• One group doesnt like to adjust electrons
  because they obey the octet rule

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Octet Rule

• An atoms outer energy level is full and most
  stable when it contains eight electrons
• All noble gases have a full outer level and obey
  this rule, meaning they dont want to give or
  receive any electrons
• Exception Helium only has two outer electrons
  and follows the Duet Rule