The Periodic Table
Horizontal Rows are called Periods.
Elements in the same period have the same number of energy
levels for ground state electron configurations.
Vertical Rows are called Families or Groups.
Families have the same valance electron
configurations.
Family 1
Alkali Metals
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Family 1
Most active of all the metals
One valance electron in outer most energy level.
(ns1: Li – 1s22s1, Na – 1s22s22p63s1)
Lose the one valance electron when forming
chemical bonds.
Form +1 ions.
All atoms “want to have an octet of valance
electron so they will gain lose or share electrons
to get to this “magic number.”
Family 2
Alkaline Earth Metals
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Family 2.
Second most active of the metals.
Two valance electrons (ns2: Be – 1s22s2,
Mg – 1s22s22p63s2)
Lose both valance electrons when forming
chemical bonds.
Form +2 ions.
Family 17
Halogens
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Family 17.
Most active of the nonmetals.
7 valance electrons (ns2np5:
F – 1s22s22p5, Cl – 1s22s22p63s23p5)
Gain 1 electron to obtain octet.
Form -1 ions.
Halogens is Greek for salt former; they
form salts when reacting with metals.
Family 18
Noble Gases – Inert Gases
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Family 18.
Most inactive of all elements.
Do not normally form compounds.
8 valance electrons (ns2np6: Ne – 1s22s22p6,
Ar – 1s22s22p63s23p6)
A perfect octet of electrons so they do not gain
or lose electrons to form compounds.
Helium is only 1s2, but it still does not form
compounds because the 1st energy level is filled
with only 2 electrons.
Group B Elements
Transition Metals
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Family 3 – Family 12
Less active than alkali or alkaline earth metals.
One or two valance electrons. All transition
metals have ns1 or ns2 valance electron
structures.
They have (n-1)d1 – (n-1)d10.
They have oxidations (ion charges) of +1
through +7.
Transition metals do not obtain octets because
they have “d” electrons involved in bonding.
Inner-transition Metals
Stair Step Line:
Divides Metals and Nonmetals
Metalloids
Metalloids
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Have properties of both metals and
nonmetals.
Semiconductors; metals are conductors
and nonmetals are nonconductors.
If element is on the metal side treat as a
metal; if it is on the nonmetal side treat
as a nonmetal.
Boron Family
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Family 13
Boron – metalloid
Aluminum and rest
are metals.
3 valance electrons.
ns2np1
+3 ion charge
Carbon Family
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Family 14
Carbon – nonmetal
Silicon and germanium are
metalloids.
Tin and lead are metals.
4 valance electrons.
ns2np2
Carbon and silicon can be +4
or -4 or it can share electrons
to form bonds.
Tin and lead can be +2 or +4.
Nitrogen Family
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Family 15
Nitrogen and phosphorus are
nonmetals.
Arsenic and antimony are
metalloids.
Bismuth is a metal.
5 valance electrons.
ns2np3
Nitrogen and phosphorus are
usually +3.
Bismuth and antimony are +3
or +5.
Oxygen Family
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Family 16
Oxygen, sulfur and
selenium are nonmetals.
Tellurium and polonium
are metalloids.
6 valance electrons.
ns2np4
Oxygen and sulfur are
usually -2.
S, P, D, F Block Elements
Noble Gas Configurations
History and Periodic Properties
of the Periodic Table
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Objective: explain the use of chemical
and physical properties in the historical
development of the Periodic Table.
Objective: use the Periodic Table to
identify and explain periodic trends,
including atomic and ionic radii,
electronegativity, and ionization energy.
The Father of the Periodic Table
Dmitri Mendeleev’s Periodic Table
History of the Periodic Table
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John Newlands: 1864
He proposed an organization scheme for the
elements.
Newlands noticed that when the elements were
arranged in order of increasing atomic mass,
their properties repeated every eight elements.
This pattern is “periodic” because it repeats at
regular intervals.
History: Part II
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Dmitri Mendeleev: 1869
He noticed the same “periodic” pattern as
Newlands.
By arranging the elements in order of increasing
atomic mass into columns with similar properties
Mendeleev credited the first periodic table.
He predicted the properties of scandium,
gallium, and germanium.
History: Part III
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Mendeleev’s table had problems.
When new elements were discovered it was
found that the order was not correct.
Henry Moseley: 1913
Mosley discovered that each element had a
unique number of protons.
He proposed that the periodic table be arranged
in order on increasing atomic number.
The Periodic Law
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There is a periodic repetition of chemical and
physical properties of the elements when they
are arranged in order of increasing atomic
number.
The properties of the elements are related to
their atomic numbers and their location on the
periodic table.
This repetition can be seen in both families and
periods.
Atomic Radius
Atomic Radius
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Atomic radius is the “size” of an atom.
Atomic radius is half the distance between the nuclei of
two atoms.
Atoms with a large atomic radius will be easy to remove
an electron from; these are usually the metals.
Atoms with a small radius are harder to remove an
electron from; these are usually the nonmetals.
Largest radius = francium
Smallest radius = helium
Ionization Energy
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Ionization energy is the
energy required to
remove one electron from
an atom.
Elements with low
ionization energies tend
to lose electrons and
form positive ions.
Metals have low
ionization energies,
nonmetals are high.
Electronegativity
Indicates the relative ability of an atom to
attract electrons in a chemical bond.