Transcript The History and Arrangement of the Periodic Table

Bellwork
►Turn
to page 167 in your textbook.
Look at the vocabulary words on the
page. Identify where these groups are
found on the periodic table.
The History and
Arrangement of the
Periodic Table
History of the Periodic Table
► 1869
– Dmitri Mendeleev (Russian Chemist)
thought elements may have something in
common.
► Organized the elements into a table
► Made each element a card and listed its
properties known at the time (mass,
density, color, melting point and valence
number).
Dmitri Mendeleev (cont.)
► Mendeleev
organized each card (element)
according to its atomic mass (mass #)
► Noticed a repeating pattern of valence
numbers (1,2,3,4,5 etc..)
► Noticed elements fell in to columns (groups)
► Noticed all elements in a column had the
same valence number and showed similar
physical and chemical properties.
Henry Moseley
► Mendeleev
left blank spaces in his table so
elements would line up – he also predicted
what properties the undiscovered elements
would have.
► 1913 – Henry Moseley (English Scientist)
changed the arrangement of the periodic
table. Instead of by increasing atomic mass
(mass #), it was arranged by increasing:
atomic number (# of protons).
Arrangement of the Periodic
Table
► Systematic
arrangement of the elements
► Arranged by atomic number and properties
► Numbered groups / families are in vertical
columns
► Periods are by amount of energy levels in
horizontal rows (1-7)
► Divided into metals, nonmetals and
metalloids
Metals - properties
► Elements
that begin at the left side of the
periodic table
► Good conductors of electricity
► Shiny
► Ductile – can be drawn into thin wires
► Malleable – can be hammered into thin
sheets and other shapes
► High melting point
► Tend to loose electrons
Nonmetals - properties
► Elements
that are to the right of the zigzag
on the periodic table
► Not shiny, dull in appearance
► Do not conduct heat or electricity
► Are brittle and break easily
► Cannot be drawn into wire or hammered
into sheets
► Lower densities
► Lower melting points
► Tend to gain electrons
Metalloids - properties
► Elements
that are found along both
sides of the zigzag line
► Solids
► Can be shiny or dull conduct heat and
electricity better than nonmetals but
not as well as metals
► Both ductile and malleable
Chemical Groups (Families)
► Elements
that are in the same group or
family (column) of the Periodic Table
have similar properties because they
have the same number of valence
electrons
Group (Family) 1 - Alkali Metals
►1
valence electron in outer energy
level
► Very reactive substances so it easily
bonds with other substances
► Easily loses 1 electron to form a stable
+1 ion (ionic bond)
► Never found alone in nature
► Soft, silver-white, shiny
Group (Family) 2 - Alkaline Earth
Metals
►2
valence electrons in outer energy level
► Loses 2 electrons to form +2 ions
► Second most reactive elements but not as
reactive as group #1, so bonds easily with
other substances
► Never found alone in nature
► Will always bond ionically in nature
► Found combined with oxygen and other
non-metals in the Earth’ crust
Groups 3-12
►1
The Transition
Metals
or 2 valence electrons
► Can lose and or share valence
electrons
► Can have many multiple electrons in
2nd to last energy levels
► Common metals – gold, silver & copper
► The U.S. imports at least 60 of these
types of elements which are strategic
and vital for our economy
From Metals to Nonmetals
(outer energy level)
►
Group 13 – Boron Group/Family
3 valence electrons
- metalloids and metals in group
- usually bonds covalently
►
Group 14
Carbon Group
4 valence electrons
- non-metals, metals and metalloids
- will always bond covalently ( electron sharing)
- contain elements which are essential for cell functions
►
Group 15
Nitrogen Group
5 valence electrons
- non-metals, metalloids and metals
- will always bond covalently
► Group 16
Oxygen Group
6 valence electrons
- non-metals, metalloids and metals
- will bond covalently and ionically in nature
►
Group 17
Halogen Group
7 valence electrons
- all non-metals that are very reactive and form compounds
called halides ( salts)
- bonds covalently and ionically
►
Group 18
Noble Gases
8 valence electrons
- colorless
- non-reactive ( inert ) / very stable
- have a full outer shell filled
with electrons
- non-metals
Rare Earth Elements
(Inner Transition Metals)
► First
Row – Lanthanide Series
- naturally found rare Earth metals
- all but one is non-radioactive
► Second
Row – Actinide Series
- most are man-made and radioactive
- many are short-lived