Transcript Periodic Table - Bruder Chemistry

Periodic Table
History
• Antoine Lavoisier – Father of Modern
Chemistry
• 1829 German J. W. Dobereiner Grouped
elements into triads
– Three elements with similar properties
– Properties followed a pattern
– The same element was in the middle of all trends
• Not all elements had triads
Law of Octaves
• 1862 John Newlands developed Law of
Octaves
• The elements showed a repetition in their
chemical properties after 8 elements
• Used Atomic Weights but not actual values
• Important because showed the first pattern of
repeating properties
Julius Lothar Meyer
• Meyer first table published 1864 containing 28
elements
• Arranged in order of Atomic Weight and made
a clear horizontal relationship between Atomic
Weight and Atomic Volume
• Allowed physical properties to outweigh
chemical properties
• Anticipated Mendeleev by years
Meyer
• Left gaps to denote unknown elements
• Not willing to make predicitions
• More focused on Physical properties not
chemical properties
• Bitter battle with Mendeleev
• Lost to Mendeleev because of Mendeleev’s
forceful ways
Dmitri Mendeleev
• Mendeleev was known as the “Father of the
Periodic Table”
• DOB: 1834-1907
• Created the first table on 3-1-1869
• Table had 70 elements
• Used properties to set up table
History
• Russian scientist Dmitri Mendeleev taught
chemistry in terms of properties
• Mid 1800 – atomic masses of elements were
known
• Wrote down the elements in order of
increasing mass
• Found a pattern of repeating properties
• Not first to develop system but his version had
the strongest impact
Mendeleev’s Table
• Grouped elements in columns by similar
properties in order of increasing atomic mass
• Found some inconsistencies - felt that the
properties were more important than the
mass, so switched order.
• Found some gaps
• Must be undiscovered elements
• Predicted their properties before they were
found
Mendeleev
• Distinguished from competitors by a devotion
to, and love for, the individuality of the
elements that went hand in hand with an
intimate knowledge of their chemical
characteristics
• Focused on both physical and chemical
properties
Mendeleyev Cont.
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I.
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Chemical Properties Used:
Atomic Weight vs. Valancey
He could only predict these properties
His work preceded chemical advances by 30 years
Produced his table 27 years before the first
subatomic particle, the electron was discovered
Did not predict Noble Gases
Acceptance
• Mendeleev’s table received real acceptance in
1875
• Discovery of Scandium, Germanium and
Gallium showed Mendeleev’s predictions
were correct.
“The elements were not being arranged to make
a periodic table, but to fit the periodic table”
Meyer vs. Mendeleyev
• Julius Meyer (18301895)
• Created a table that
plotted:
• Atomic Volume vs.
Atomic Weight
• Lost out to Mendeleev
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Published before Meyer
Final Table:
Atomic Weight vs. Valency
Table had 8 columns but
was missing Noble Gases
• Discovered 30 years later
Modern Russian Table
Spiral Periodic Table
Changing of Table
• Henry Moseley (1887-1915) – changed table
in 1913 by increasing atomic number
• Biggest Impact
• Glenn Seaborg – rare earth series from
Actinium (89) up.
• Current Table Used Today
• Minor Changes – inner transitional Lu & Lr
replaced La & Ac
• Bohr first linked Quantum Theory
Today’s Table
More History
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1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
First Elements Discovered:
Carbon
Sulfur
Copper
Gold & Silver
Iron
Tin
Antimony
Mercury
Lead
Oxygen (1772)
•
1.
2.
3.
4.
First Classified Groups:
Gases
Non-Metals
Metals
Earths
The Modern Periodic Table
•
•
Our current periodic table shows elements in
order of increasing atomic number (#protons)
Elements in the same column have similar
properties, and are called a group or family.
Groups are designated in two ways:
1. A Roman numeral (I through VIII) and a letter (A or
B)
2. An Arabic number (1-18)
•
A horizontal row of elements is a period.
Elements in the same period have properties that
tend to vary in a regular fashion. Periods are
designated by an Arabic number (1-7).
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Vertical Columns
• Known as Groups or a Family
• Elements in same group have similar physical
& chemical properties
• Each group is identified by a group number
and group letter
Groups and Periods
Figure 2.19
2-25
Similar Properties in Groups
• Potassium metal reacts
violently with water to
producing a basic
solution and flammable
hydrogen gas.
• All alkali metals react
with water to produce
hydrogen gas.
Figure 2.21
2-26
Classification of Elements
• Groups
– IA Alkali metals
– IIA Alkaline Earth Metals
– VIIA Halogens
– VIIIA Noble Gases
• Periods
• Metals, Nonmetals, Metalloids
• Main-group Elements, Transition
Metals, and Inner-transition
Metals.
Figure from p. 73
2-27
Main-Group Elements and Transition
Metals
• Main-group elements (also called representative
elements) contain any element in the eight groups
designated with the letter A. (In the Arabic
numbering, groups 1, 2, and 13-18)
• Transition metals contain any element in the 10
groups designated with the letter B. (In the Arabic
numbering, groups 3-12)
• Inner-transition metals contain the lanthanides and
actinides listed separately at the bottom of the
table.
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Common Group Names
• Some groups have descriptive names that are commonly
used instead of their group numbers.
– Alkali metals
• Group 1 (IA) metals (hydrogen is a nonmetal)
• are considered reactive because the react readily with
other elements and compounds
– Alkaline earth metals
• Group 2 (IIA) metals
• are more reactive than the transition metals but less
reactive than alkali metals
2-29
Common Group Names
• Some groups have descriptive names that are commonly
used instead of their group numbers.
– Halogens
• Group 17 (VIIA) nonmetals
• exist naturally as diatomic molecules
– Noble gases
• Group 18 (VIIIA) nonmetals
• are also called inert gases
• are so named because they do not chemically react
with other elements (with the exception of krypton
and xenon)
2-30
• The elements in the A groups are
called the representative elements
1A
2A
3A 4A 5A 6A 7A
8A0
Transition metals
• The Group B
elements
VIIIB
IIB
VIIB
VIB
VB
13 14 15 16 17
3A 4A 5A 6A 7A
IB
VIIIA
VIIA
VIA
VA
IVA
IIIA
IIIB
1 2
1A 2A
IVB
IIA
IA
Other Systems
3 4 5 6 7 8 9 10 11 12
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
18
8A
• Horizontal rows are called periods
• There are 7 periods
• Group 1A are the alkali metals
• Group 2A are the alkaline earth metals
• Group 7A is called the Halogens
• Group 8 are the noble gases
The group B are called the
transition elements
 These
are called the inner
transition elements and they
belong here
Metals, Nonmetals, and Metalloids
• The periodic table has many classifications. Groups and
periods are one classification. Another classification
denotes metals, nonmetals, and metalloids.
– A stair-step line starting at boron (B) separates metals
(to the left of the line) from nonmetals (to the right of
the line).
– The metalloids exist along the line.
• Metalloids are elements that have physical
properties resembling a metal, but the chemical
reactivity of a nonmetal.
2-39
Metals
Metals & Their Properties
• Metals are good conductors of heat and
electricity
• Metals are malleable
• Metals have high luster
Example of Metals
• Copper is a relatively soft metal and a very good
electrical conductor
• Mercury is the only metal that exists as a liquid at
room temperature
Non-metals
Nonmetals & Their Properties
• Carbon, the graphite in a pencil is an
example of a nonmetallic elements
• Nonmetals are poor conductors of
electricity
• Can be brittle
• Non-lustrous
• Many are gases at room temperature
Example of Nonmetals
• Sulfur was once known as Brimstone
• Microspheres of phosphorus, a reactive
nonmetal
Metalloids or Semimetals
• Properties of both
• Semiconductors
Example of a Metalloid
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Silicon is a metalloid
Silicon is brittle like a nonmetal
Silicon has metallic luster
Silicon is a semiconductor of electricity
Metals, Nonmetals, and Metalloids
Figure 2.20
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Modern Periodic Table
Elements
are
divided
into two
main
classes
EOS
Chapter 2: Atoms, Molecules, and Ions
49
Modern Periodic Table
Except for
hydrogen,
those
elements to
the left of the
line are
metals
EOS
Chapter 2: Atoms, Molecules, and Ions
50
Modern Periodic Table
Elements to
the right of
the line are
nonmetals
EOS
Chapter 2: Atoms, Molecules, and Ions
51
Modern Periodic Table
Elements
around the
line are
referred to as
metalloids
EOS
Chapter 2: Atoms, Molecules, and Ions
52