Transcript 3.2 PowerPoint

3.2 Using the Periodic Table
Objectives
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Relate an element’s valence electron
structure to its position in the periodic
table.
Use the periodic table to classify an
element as a metal, nonmetal, or
metalloid.
Compare the properties of metals,
nonmetals, and metalloids.
New Vocabulary to Look for…
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Period
Group
Noble gas
Metal
Transition element
Lanthanide
Actinide
Nonmetal
Metalloid
semiconductor
Relationship of the Periodic
Table to Atomic Structure
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Periodic tables contain a vast array of
information on the elements.
You will learn to use the periodic table to
gather information about the elements and
group of elements we are studying.
Modern periodic table is arranged according
to increasing atomic number.
What information does the atomic number tell
us?
Periods and Groups
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The horizontal rows of the periodic
table are called periods.
The vertical columns are referred to as
groups.
Groups are also called families of
elements.
Elements in the same group have
similar properties.
Atomic Structure of Elements
Within a Period
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Each period starts with a group 1 element,
which has 1 valence electron.
As you move across a period the number of
valence electrons increases. Moving from 1,
2, 13, 14, 15, 16, 17, 18.
Group 1 elements have one electron at a
higher energy level than the noble gas of the
preceding period.
Atomic Structure of Elements
Within a Group
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The number of valence electrons can be
predicted using the periodic table.
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Group 1 has 1 valence electron
Group 2 has 2 valence electrons
Groups 13-18 have the second digit of
valence electrons.
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13 has 3 valence electrons
14 has 4 valence electrons
Fig. 3.8 p. 98
Noble Gases
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Group 18 have the periodic table.
They have 8 valence electrons, except
for He which only has 2
Full energy levels
Generally unreactive or inert
Ne, He, Ar
Noble Gases
Halogens
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Greek meaning “salt former”
Form salt like compounds
Group 17
7 valence electrons
F, Cl, Br, I
Alkali Metal
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Group 1 (except H)
1 valence electron
Li, Na, K
Alkali Metals
Alkaline Earth Metals
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Group 2
2 valence electrons
Be, Mg, Ca, Ba
Valence Electrons-Properties
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Valence electrons help to determine the
physical and chemical properties
Groups have similar properties b/c they
have the same number of valence
electrons
Fig. 3.9 p. 99 Electrons in Energy
Levels-Group 16
Physical States and Classes of
Elements
Physical States of the
Elements
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The physical states of the elements are show
on the periodic table on p. 92-93.
Most elements are solids at room
temperature
Only two are liquids. What are they?
A.
B.
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All the gases except hydrogen are in the
upper right corner of the table. List some.
Gallium
Classifying Elements
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Elements are classified into groups
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Majority of elements are metals
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Left side and center
Nonmetals
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Metals
Nonmetals
Metalloids
Upper right corner
Metalloids
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Along the boundary b/t metals and nonmetals
Metals
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Have luster
Conduct heat
Good conductors of electricity
Most have high boiling pts.
Malleable
Ductile
Most are solid
Only one metal is in the liquid state.
Metals
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Most are located in Groups 1-13
Transition Elements- Elements in Group 312 (all metals)
Iron (Fe), nickel (Ni), Copper (Cu), Zinc (Zn)
Some of period 7 are synthetic and
radioactive
The transition elements have a less
predictable behavior and properties than the
other metals
Transition Elements
Transition Elements
Transition Elements
Metals
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Elements with the atomic numbers 5871 and 90-103 are placed below the
main table
If they were part of the main table it
would be extremely wide
Known as the inner transition elements
Many were unknown in Mendeleev’s
time
Inner Transition Elements
Lanthanides
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First series of inner transition elements
14 elements 58-71
Also called rare earth elementsabundance 0.01%
All have similar properties
Actinides
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Second series of inner transition
elements
90-103
Radioactive
None beyond uranium occur in nature
Unpredictable-complex structures
Nonmetals
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Nonmetals are abundant in nature
Oxygen and nitrogen make up 99% of
our atmosphere
Carbon is found in more compounds
than all the other elements combined.
Nonmetals
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Don’t conduct electricity
Poor conductors of heat
Brittle when solid
Many are gases at room temp.
Solids lack luster
Melting points and boiling points are low
Table 3.5 p. 105 Properties of Metals and
Nonmetals
Metalloids
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Have properties of both metals and
nonmetals
Located between the metals and nonmetals
Si, Ge and As are semiconductor
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Does not conduct electricity as well as a metal,
but does better than a nonmetal
Si semiconductors made the computer
revolution possible.
Atomic Structure of Metals,
Metalloids and Nonmetals
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Differences occur b/c of the different
arrangements of electrons
Number, arrangement of valence
electrons along with how tightly they
are held in the atom determines the
behavior.
Valence electrons in Metals
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Loosely bound
Free to move in the solid metal
Easily lost
Freedom of movement = conductivity
Valence electrons in Nonmetals
and Metalloids
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Tightly held
Not easily lost
Chemical Reactions and Electrons
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Metals tend to lose valence electrons
Nonmetals tend to share or gain
electrons
General Properties and Uses of
Metals, Nonmetals and Metalloids
Familiar Metals
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Some Lanthanides and Actinides
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Compounds of europium and ytterbium – picture tubes of TV
Neodymium – high powered lasers
Carbon and Some Other Nonmetals
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Carbon: Coal, natural gas, oil, graphite, diamonds
Bromine and Iodine – halogen lamps
Metalloids
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Jewelry, figurines, electrical circuits
Silicon – electronic devices
Page 106-107
Semiconductors
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Metalloids that do not conduct
electricity as well as metals, but better
than nonmetals
Uses
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Television
Computer
Handheld electronic games
Calculators
Semiconductors –Electrons
and Electricity
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An electrical current is flowing electrons.
Metals conduct electricity well because the
electron are not tightly held by the nucleus
and are therefore free to move.
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Copper wire
At room temperature Si is not a good
conductor. Its four electrons are tightly held
by the nucleus.
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In order to make it a good conductor it must be
doped with another element.
Silicon (Si)
Doping of Si
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By adding small amounts of P to Si a
good conductor is created.
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P has five valence electrons. This adds an
extra electron which is free to move =
electrical conductivity.
n-type semiconductor (negatively charged)
Doping of Si
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By adding B to Si a good conductor is
created
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B has three valence electrons. The
shortage of electrons creates “holes” in
which the electrons can move = electrical
conductivity.
p-type semiconductor (positively charged)
Diodes
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The combination of n-type and p-type
semiconductors is a diode.
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Permits electrical flow in only one direction
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Negative terminal to positive terminal
Transistors
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Key components in electrical circuits,
amplifying the electrical signal.
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npn-junction
pnp-junction
Review
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Where are the halogens, noble gases,
alkali metals, alkaline earth metals,
lanthanide and the actinides located?
Give me an example of each?
What are the characteristics of a
metal, nonmetal and metalloid?
How many valence electrons does Li
have?
Using the Periodic Table