History of the Periodic
Table
Each group will be given some cards. Can your group
figure out what card is missing? What is it (number
and suit)?
Antoine Lavoisier


1743 - 1794
In the late 1790s,
he compiled a list
of the known
elements at the
time.
This list contained
23 elements.
But times were about to change…

In the 1800’s, there were many
changes in the world
• Electricity
• Spectrometer
• Industrial Revolution

As a result, there was an increase in
the number of known elements
• By the 1870, there were 70 known
elements
An agreement is reached…

Then in the 1860’s, chemist agreed
upon a method for accurately
determining the atomic mass of
elements.
John Newlands


1838-1898

Noticed when elements
were arranged by atomic
mass, they repeated
properties every 8th
element.
He used the word
periodic to describe this
pattern
He gave it the name the
Law of Octaves
Unfortunately…



Did not work for all the elements
Criticized because of its association with
music
Did give others the idea of repeating
properties - periodic
We Hate It
Lothar Meyer and Dmitri Mendeleev
1830-1895

1834 - 1907
Each made a connection between
atomic mass and properties of
elements
The winner is…
Mendeleev


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Mendeleev is given credit because
his was published first
In addition, Mendeleev predicted
unknown elements
However, not completely correct –
new elements weren’t in correct
order
What do you notice about elements
27 & 28 and 52 & 53?
Henry Moseley


1887-1915
Solved this problem by
arranging the elements
by increasing atomic
number.
The periodic repetition
of chemical and
physical properties of
elements when
arranged by atomic
number is now known
as Periodic Law
Which leads to the Modern Periodic
Table

Boxes each with:
Element
Name
Atomic
Number
Hydrogen
1
H
1.00794
Atomic
Symbol
Atomic
Mass
That are arranged by increasing atomic numbers
Remember


Atomic number = the number of
protons = the number of electrons (if
neutral)
Atomic Mass on the Periodic table is
the average mass of the isotopes
• But the mass number of each isotope is
the protons plus the neutrons
Chemical Symbol
The symbol that refers to the element
 First letter is capitalized, second letter (if
applicable) is lower case
 Not all symbols are based on English
names for the elements, some come from
their Latin names or even other languages
– Tin – Sn – stannum
– Silver – Ag – argentum
– Iron – Fe - ferrum
– Antimony – Sb -stibium
– Mercury – Hg - hydrargyrum – Lead – Pb – plumbum
– Gold – Au - aurum
– Copper – Cu – cyprium

Columns and Rows

The columns are called Families or
Groups
• Earlier Version had 1-8 followed by A or B


Group A elements are called Representative Elements
Group B elements are called Transition Elements
• Modern Version labels the columns with 1-18

Rows are called Periods
• Seven periods for the seven energy levels (rings)
Classifying Elements

Three Types of Elements
• Metals
• Nonmetals
• Metalloids
Metals


Shiny when smooth and clean
Solid at room temperature
• Only exception - Mercury


Good conductors of heat and
electricity
Most are ductile and malleable
Most of the elements on the table are
metals, which are in blue
Nonmetals



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Upper Right side of the Periodic Table
Generally brittle solids or gases
Poor conductors of heat and
electricity
Bromine is the only liquid at room
temperature
“The Yellow Elements”
Metalloids


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A.k.a – the semi-metals
Boxes bordering the stair-step
Physical and chemical characteristics
of both metals and nonmetals
“The Green Stair-stepping Elements”