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Learning Target: Classify elements according to their location on
the Periodic Table

This is a brief review of that information.
Identify the following as being an alkalai metal,
alkaline earth metal, transition metal, semi-conductor
(aka metalloid), halogen, or noble gas:
 Germanium
 Tungsten
 Potassium
 Radon
 Strontium
 Uranium
 Silicon
 Beryllium
 Palladium
 Iodine
 Which
of the following are main-group
elements?
 Magnesium
 Vanadium
 Antimony
 Lead
 Neptunium
 Cesium
 Rutherfordium
 Boron
 Indium
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Section 1:
Who’s Who???
Learning Target: Explain the development of Periodic Law
 1817
– Dobereiner
• Grouped elements in TRIADS…
• Three elements with similar properties
 1865
– Newlands
• Arranged by increasing atomic MASS.
• Law of Octaves = Similar properties
over EIGHT elements
 1870
– Mendeleev
• Created an 8
Column table based
on ATOMIC MASS
• Elements with
similar properties
were in the same
column
• Problems w/ Mendeleev’s table:
1.
Some elements did not fit the order he
described.
Ex: Tellurium (Te) and Iodine (I): he put them out of
order in terms of atomic mass, but did this so they were in
the same column as elements with similar properties (he
broke his own rules)
2.
There were gaps in the table
• BUT he was able to predict the properties and
masses of the unknown elements very
accurately.
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 1913
– Moseley
1944
• Studied X-ray spectra of
elements and noticed they
correlated with atomic number
• Arranged elements with
increasing ATOMIC NUMBER
 PERIODIC
–Glenn Seaborg
Last
rearrangement of
the periodic table –
created the actinide
series
LAW:
• Properties of the elements are a
(periodic) function of their
atomic number
1817
1865
Dobereiner
Newlands
Triads
Law of
Octaves
1870
1913
1944
Mendeleev
Mosley
Seaborg
First 8
column
table
Periodic Law
Actinide
Series
Section 2
 Atomic
properties are determined by
ELECTRON CONFIGURATION.
Ex. 1s2 2s2 2p6 3s2 3p3
 Therefore…the
table is designed on the
basis of electron configuration…
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 Valence
Electrons: Electrons that are
found in an atom’s outer most shell
 Determines chemical properties of an
atom
 These are the electrons that can be
gained, lost or shared when forming
compounds
 OCTET
RULE…
• 8 electrons in the outer energy level renders an
atom UNREACTIVE
• Unreactive = Very Stable
• So…which elements are considered unreactive?
A: The Noble Gases
 Atoms
react with other atoms so all atoms
end up with FULL OUTER ENERGY
LEVELS (i.e. compounds)
1. They may add electrons
2. They may lose electrons
3. They may share electrons
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Don’t
Section 3
forget your color-coded
periodic table…
It identifies the…
• Groups
• Periods
• Main Group Elements
Learning Target: Identify properties of metals,
nonmetals and metalloids
 It
also classifies elements as…
• Metals:
 Alkali metals
 Alkaline Earth metals
 Transition metals
Metals
–On the LEFT of the stairs
– On the RIGHT of the stairs
Metalloids – Attached to stairs
Nonmetals
 Lanthanide Series
 Actinide Series
 Other Metals
• Nonmetals:
 Noble gases
 Halogens
 Other nonmetals
• Metalloids:
 semiconductors
METALS
NONMETALS
1. Typically Solids
1. Gasses or BRITTLE solids
2. Shiny
2. Dull
3. Conduct Heat and
Electricity
3. Insulators
4. Tendency when forming 4. Tendency when forming
compounds to lose
compounds to GAIN or
outer electrons
SHARE electrons
RULE of THUMB



Metals:
• 3 or fewer outer energy level electrons
Nonmetals:
• 5 or more outer energy level electrons
Metalloids:
• Properties of both Metals and Nonmetals
• aka Semiconductors
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What
Section 4
is a trend?
A
predictable change in a
particular direction
Learning Target: Describe element trends on the
Periodic Table
(FOCUS
ON MAIN GROUP
ELEMENTS)
Atomic Radii

½ the distance between
the nuclei of identical atoms
that are bonded together
Atomic Radii increase
from top to bottom and from
right to left on the periodic
table
Increases
Increases

Radius = d/2

Periodic
Table
Increases as you move down due
to electron shielding
• electrons in the inner energy
levels are between the nucleus
and the outer electrons and
therefore are shielded from
being pulled away
• **More energy levels as you go
down PT
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
Decreases as you go right due to
increasing charge of the nucleus
(**means increases as you go left due to
decreasing charge of nucleus)
• although more electrons are also present
they are at the same distance from the
nucleus b/c they are in the same energy
level
• Stronger force of attraction, pulling
electrons closer—making radius smaller
Gallium
Thallium
Yttrium
Strontium
Helium
Neon
Hafnium
Vanadium
Ions
 Atom
or group of atoms that has a
positive or negative charge
• Positive charge occurs when atom loses
electrons
 This
process that results in an ion
requires energy—this process is referred
to as ionization
 Ex: Na+: Sodium that has lost an electron, and
now has 10 e• Negative charge occurs when atom gains
electrons
 Ex: Cl-: Chlorine that has gained an electron,
and now has 18 e-
Ionization Energy
required to remove one
electron from a neutral atom of an
element
• This happens when compounds form

Ionization energy tends to increase
from bottom to top and left to right
Increases
Increases
Energy
Periodic
Table
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As
you move across, the nucleus
gets larger and holds the
electrons more tightly
THEREFORE harder to remove
Requires
MORE energy (higher
ionization energy)
As
you move down, the outer
most electrons are farther away
from the nucleus THEREFORE
easier to remove
Iron
Cobalt
Cesium
Rhenium
Sulfur
Tin
Iodine
Bismuth
Requires
LESS energy (lower
ionization energy)
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