Warmup

1
Warm-up

• Please answer in complete sentences.
• What information about an atom does an atomic
  number provide?
• What information about an atom does the atomic
  weight provide?

2
Why is the Periodic Table important to me?

• The periodic table is the most useful tool to a
  chemist.
• It organizes lots of information about all the
  known elements.

3
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.

4
Dmitri Mendeleev

• Published in 1869
• Arranged 63 elements according to atomic weight
• Predicted the existence and properties of new
  elements

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Dmitri Mendeleev Father of the Table

• HOW HIS WORKED
• Put elements in rows by increasing atomic weight.
• 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 weight
  to keep similar reacting elements together.

6
The Current Periodic Table

• Mendeleev wasnt too far off.
• Now the elements are put in rows by increasing
  ATOMIC NUMBER!!
• 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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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 TableColumns 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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The Element Boxes
atomic number number of protons in the nucleus,
defines an element (equal to the number of
electrons in a neutral atom)
Symbol
atomic number
symbol one or two letter code for an element.
Symbols do not always match the names.
mass number or atomic mass
mass number number of protons number of
neutrons in an isotope
atomic mass weighted average mass of the natural
isotopes of an element.
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Diatomic elements H2, N2, O2, F2, Cl2, Br2, I2
14
number of valence electrons by group (family)
1
8
2
3
4
5
6
7
15
1
0
oxidation numbers by group (family)
4 -4
2
3
-3
-2
-1
variable
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General Properties of Metals
Metals account for about 75 of the elements

• Solids at room temperature (except mercury)
• Lustrous (shiny, reflect light)
• Malleable (can be shaped)
• Ductile (can be stretched)
• Good conductors of heat and electricity
• Give up electrons easily

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Group 1 2 Metals

• Alkalis
• Softest metals
• 1 valence electron
• easy to remove
• 1 oxidation
• Most reactive metals
• React strongly with water
• Not found pure
• Form basic solutions

• Alkaline-earths
• Harder than alkalis
• 2 valence electrons
• easy to remove
• 2 oxidation
• Less reactive
• React with water
• Not found pure
• Form basic solutions

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Groups 3-12 Metals

• Transition Metals
• Biggest subdivision of the periodic table
• Harder than groups 1 2
• Less reactive than groups 1 2
• Higher melting and boiling points than groups 1
  2
• Variable valence oxidation
• Often form colorful solutions
• Precious metals (silver, gold, platinum)
• Iron, cobalt, and nickel are magnetic

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Inner Transition Metals (Rare Earth)

• Belong in the periodic table but are taken out to
  allow the table to fit on one page
• Consist of lanthanides and actinides
• Many are man-made and radioactive
• Some have magnetic properties
• Used in superconductors
• Fluoresce under UV

21
Metalloids (Semi-metals)

• Similar in appearance to metals but have
  different crystal structures.
• Sometimes react like metals and sometimes
  non-metals depending on the chemicals they are
  reacting with

• Semiconductors are made from silicon, boron, and
  germanium. Semiconductors only conduct
  electricity under special conditions. Used to
  make electronic devices like computers,
  calculators, MP3 players.

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General Properties of Nonmetals

• Good insulators (poor conductors)
• Solids are brittle
• Solids are dull (no luster)
• 3 - 8 valence electrons
• Gain electrons easily (except noble gases)

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Other Nonmetals

• These elements form compounds that are the basis
  of life DNA, sugars, fats, proteins, and water.
• Hydrocarbons are used for heating, cooking, and
  transportation fuels.
• Graphite and diamonds are both forms of carbon.
• Nitrogen and oxygen are the primary components of
  air.
• Phosphorus is used in matches.
• Sulfur is used in fertilizers and many
  manufacturing processes

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Halogens - Group 17

• 7 valence electrons
• Highly reactive group
• F is the most reactive element
• Used in water purification, antiseptics,
  bleaches, pesticides, and photographic processes.

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Noble Gases - Group 18
2
He

• Non-reactive (inert)
• Full outer shells
• Low m.p.s and b.p.s
• Used in lights, lasers, welding, and cryogenic
  research.

helium
10
Ne
neon
18
Ar
argon
36
Kr
krypton
54
Xe
xenon
86
Rn
radon