The Periodic Table of Elements

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The Periodic Table of Elements

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(No Transcript)
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Periodic ? Periodic Table

• Something periodic occurs at regular or at least
  generally predictable intervals
• Periodic Table of Elements a table of the
  elements, arranged by atomic number, that shows
  the patterns in their properties

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Element

• A pure substance made up of one kind of atom that
  cannot be broken down into simpler substances by
  physical or chemical means
• 94 occur naturally on earth
• 24 were synthesized (made) by scientists

Element Song
http//www.youtube.com/watch?vzUDDiWtFtEM
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Dmitri Mendeleev

• In the 1860s he devised a periodic table where
  the elements were ordered by their atomic masses
• He did this by grouping elements together
  according to their similarities

Image taken from http//jscms.jrn.columbia.edu/c
ns/2006-04-18/fido-luxuriantflowinghair/mendeleev/

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Mendeleevs Published Periodic Table of Elements
Why do you think there are question marks here?
Image taken from http//www.chemsoc.org/networks/
learnnet/periodictable/post16/develop/mendeleev.ht
m
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Mendeleevs Predictions

• Although Mendeleevs Periodic Table of Elements
  had missing elements or gaps, he was able to
  predict the characteristics of these missing
  elements because of Periodic Law.

Ekasilicon
Germanium
Notice how Mendeleevs predictions (orange
column) were very accurate when compared to
Germaniums actual characteristics (green column)
Date Predicted 1871 Date Discovered 1886
Atomic Mass 72 Atomic Mass 72.6
Density 5.5 g/cm3 Density 5.47 g/cm3
Bonding Power 4 Bonding Power 4
Color Dark Gray Color Grayish White
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Henry Moseley

• In 1914, his work led to a revision of the
  periodic table by rearranging the elements by
  their atomic numbers (not atomic masses)
• He concluded that the number of protons in an
  atom is its atomic number

Image taken from http//dewey.library.upenn.edu/
sceti/smith/
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3 Classes of Elements
Class Color
Metal
Non-Metal
Metalloid
Using this as a guide, color code your periodic
table to show the three classes. Start by
highlighting the zig-zag.
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Metals

• Location
• Found on the left of the zigzag line/staircase on
  the periodic table (exception ? Hydrogen)
• Chemical Properties
• Have few electrons in their outer energy level,
  thus lose electrons easily
• Physical Properties
• Ductile (able to be drawn out into a thin wire),
  good conductors, malleable (able to be hammered
  without breaking or cracking), shiny, most are
  solid _at_ room temperature

79 Au 196.967
11 Na 22.990
Image taken from http//chemistry.about.com/od/p
eriodictableelements/ig/Element-Photo-Gallery.--98
/Sodium.htm
What metal is not a solid _at_ room temperature?
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Atoms with Few Electrons in their Outer Energy
Level
11 Na 22.990
Notice only 1 electron in outer level
4 Be 9.012
Notice only 2 electrons in outer level
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Non-Metals

• Location
• Most found to the right of the zigzag
  line/staircase on the periodic table
• Chemical Properties
• Most have almost full outer energy levels, thus
  they tend to gain electrons some have
  completely full outer level
• Physical Properties
• not ductile or malleable, not shiny, poor
  conductors, most are solid, but some are gas at
  room temperature

17 Cl 35.453
Image taken from http//nobel.scas.bcit.ca/resou
rce/ptable/cl.htm
16 S 32.066
Image taken from https//www.dmr.nd.gov/ndgs/rock
andmineral/sulfur.asp
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Atoms with Full or Almost Full Outer Energy Level
8 O 15.999
Notice 2 electrons in outer level FULL
2 He 4.003
Notice 6 electrons in outer level almost full
Notice 7 electrons in outer level almost full
9 F 18.998
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Metalloids

• Location
• Border the zigzag line/staircase on the periodic
  table
• Chemical Properties
• Most atoms have ½ () complete set of electrons
  in outer level
• Physical Properties
• have properties of both metals and non-metals

14 Si 28.086
Image taken from http//library.thinkquest.org/C
0113863/bios.shtml
5 B 10.811
Image taken from http//library.thinkquest.org/C
0113863/bios.shtml
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Atoms with ½ () Complete Outer Energy Level
Notice only 4 electrons in outer level
5 B 10.811
Notice only 3 electrons in outer level
14 Si 28.086
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Important Features of the Periodic TablePeriod
(Row)

• each horizontal row of elements on the periodic
  table

How many periods (rows) are on the Periodic
Table Of Elements?
FROM LEFT TO RIGHT OR RIGHT TO LEFT
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Period (Row) Properties

• Seven periods on a periodic table (numbered from
  the top down)
• Atomic numbers and atomic masses increase as you
  move from the left to the right in a period
• All atoms of the elements in the same period have
  the same number of orbitals/levels
• All atoms of the elements in a specific period
  have that respective number of orbitals/levels
• Example
• Period 1 1 orbital
• Period 2 2 orbitals
• Period 3 3 orbitals
• Etc

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• Each row is called a period
• Elements in each period have the same number of
  energy shells

Periods
1st Period 1 Shell 2nd Period 2 Shells 3rd
Period 3 Shells 4th Period 4 Shells
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Examples of Period (Row) elements having the same
number of orbitals/levels in their atoms
In what period (row) do you think these atoms
reside?
In what period (row) do you think these atoms
reside?
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Important Features of the Periodic Table Group
(Family)

• each column of elements on the periodic table

How many groups (families) are on the Periodic
Table Of Elements?
FROM TOP TO BOTTOM OR BOTTOM TO THE TOP
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Group (Family) Properties

• Eighteen groups on the periodic table (numbered
  from left to right)
• Atomic numbers and atomic masses increase as you
  move from the top down in a group (family)
• Atoms of elements in the same group have the same
  number of electrons in the outer orbital/levels
  of their atoms (known as valence electrons)
• Exceptions
• Transition elements (3-12)
• Hydrogen (has no neutron)
• Helium (actually has 2 valence electrons)
• Elements in groups usually have similar physical
  and chemical properties

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Groups / Families
Group 1 1 electron Group 2 2 electrons
Group 8 8 electrons
3, 4, 5, 6, 7
Except for He, it has 2 electrons

• Each column is
• called a group
• Each element in a
• group has the same
• number of electrons
• in their outer orbital,
• also known as shells
• The electrons in the
• outer shell are called
• valence electrons

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Examples of Group Elements with the same of
valence electrons
How many electrons do each of these atoms have in
their outer orbital/level?
What group (family) do these elements reside in?
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Group (Family) Names
Halogens
Nitrogen Group
Alkali Metals
Alkaline Earth Metals
Boron Group
Noble Gases
Carbon Group
Oxygen Group
Transition Metals
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Transition Elements

• Transition Metals
• have slightly
• different rules
• for shells and
• valence electrons

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Transition Elements
This is something you will learn about in High
School Chemistry. They are all metals which are
harder than alkali metals and less reactive with
water. Their name denotes their central location
on the periodic table. Here you find some well
known elements like iron, copper, nickel, silver
and gold. Because some are noncorrosive they are
used in implant devices.
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Identify the Element
Period 2 Group 14 ?
Carbon - C
Period 5 Group 2 ?
Strontium - Sr
Group 17 Period 6 ?
Astatine - At
Group 4 Period 7 ?
Rutherfordium - Rf
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Using the Periodic Table

• The boxes that make up the periodic table contain
  a significant amount of information. To
  understand this information, it is necessary to
  refer to the periodic tables key(s)

8 O Oxygen 15.999
Atomic Number (Number of protons)
Element Symbol (Written with a capital letter or
a capital followed by a lower case if two letters
)
Element Name
Atomic Mass (Rounded to a whole number, equals
the number of protons and neutrons)
Class Color
Metal
Non-Metal
Metalloid
State (_at_ Room Temp.) Symbol Color
Solid
Liquid
Gas
What is Oxygens physical state of matter?
Which class does Oxygen fall into?
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Determine the number of shells and the number of
valence electrons for
Carbon - C
2nd Period 2 shells
4th Group 4 valence electrons
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Determine the number of shells and the number of
valence electrons for
Sodium - Na
3rd Period 3 shells
1st Group 1 valence electron
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Write your answers on your handout.
Ne
Name the element. Number of shells ? Valence
electrons ?
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Write your answers on your handout.
Ne
Neon
Name the element. Number of shells ? Valence
electrons ?
2nd Period 2 shells
8th Group 8 valence electrons
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Write your answers on your handout.
H
Name the element. Number of shells ? Valence
electrons ?
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Write your answers on your handout.
H
Hydrogen
Name the element. Number of shells ? Valence
electrons ?
1st Period 1 shell
1st Group 1 valence electron