The Periodic Table and How it
is Organized.
Why is the Periodic Table
important to me?
• The periodic table is
the most useful tool to
a chemist.
• It organizes lots of
information about all
the known elements.
Pre-Periodic Table Chemistry …
• …was a mess!!!
• No organization of
elements.
• Imagine going to a
grocery store with no
organization!!
• Difficult to find
information.
• Chemistry didn’t make
sense.
Dmitri Mendeleev: Father of the
Table
HOW HIS
WORKED…
• Put elements in rows
by increasing atomic
weight.
• Put elements in
columns by the way
they reacted.
SOME
PROBLEMS…
• He left blank spaces
for what he said were
undiscovered
elements. (Turned
out he was right!)
• He broke the pattern
of increasing atomic
weight to keep similar
reacting elements
together.
• http://en.wikipedia.org/wiki/Dmitri_Mendele
ev
The Current Periodic Table
• Mendeleev wasn’t too far off.
• Now the elements are put in rows by
ATOMIC
NUMBER!!
increasing
• The horizontal rows are called periods and
are labeled from 1 to 7.
• The vertical columns are called groups
and are labeled from 1 to 18.
Elements are arranged:
Vertically into Groups
Horizontally Into Periods
Why?
If you looked at one
atom of every element
in a group you would
see…
Each atom has the same number of
electrons in it’s outermost shell.
• An example…
The group 2 atoms all have 2 electrons
in their outer shells
Be (Beryllium)
Atom
Mg (Magnesium) Atom
• The number of outer or “valence” electrons
in an atom effects the way an atom bonds.
• The way an atom bonds determines many
properties of the element.
• This is why elements within a group
usually have similar properties.
If you looked at an atom from each
element in a period
you would see…
Each atom has the same number of
electron holding shells.
An example…
The period 4 atoms each have 4 electron
containing shells or orbits.
4th Shell
K (Potassium)
Kr (Krypton)
Atom
Atom
Fe (Iron) Atom
Each group has distinct properties
• The periodic Table is divided into several
groups based on the properties of different
atoms.
• Use your blank periodic table to outline
each group.
• Write the title for each group.
• Write the properties of each group within
the outlined area of the group.
Alkali Metals
•Soft
•Silvery colored
•Metals
•One valence
electron
•Very reactive!!!
Alkali Metals reacting with water:
•
•
•
•
•
•
Li (Lithium)
Na (Sodium)
K (Potassium)
Rb (Rubidium)
Cs (Cesium)
Fr (Francium)
Alkaline Earth Metals
•Silvery-White Metals
•Fairly reactive
•Good Conductors of
electricity
•Two Valence Electrons
•Many are found in rocks in
the earth’s crust
Transition Metals
•Hard
•Shiny
•Good
Conductors
•Fairly
Stable
•Malleable (easily
bent/hammered into
wires or sheets)
How many things can you think
of that have Transition Metals in
them?
Other Metals (poor metals)
•Ductile (can be pulled out into
wire or thread shape), Malleable,
Solids,
• High Density
•Opaque (not transparent)
•Do not oxidize as transition
metals do
•They share properties with both
metals and non-metals
•Si (Silicon) and Ge
(Germanium) are very important
“semi-conductors”
What are semiconductors used in?
Nonmetals
•Dull not shiny
•Not malleable
•Not ductile
•Brittle as solids
•Do not conduct electricity
•Some are gases at room temp.
•Metals and nonmetals form
compounds where electrons move
from the metal to the nonmetal
Nonmetals
What about Hydrogen??
•Simplest element with one
electron and one proton
•Makes up 90% of the universe
•Chemical properties are different
from any other group
•Hydrogen sits atop the periodic
table as an independent
Halogens
•Most are Poisonous
•Seven valence
electrons
•Range from gases to
liquids to solids at room
temp.
•Highly reactive
especially with Alkali
Metals and Alkaline
Earth Metals
Chlorine Gas was used as a
chemical weapon during World
War I.
It was used by the Nazis in World
War II.
Yet when mixed with sodium,
harmless table salt (NaCl) is the
result
Noble Gases
•Unreactive
•All present in Earth’s
atmosphere in small
amounts
•Gases at room
temperature
•Used in Neon lights
Jellyfish lamps made with noble
gases artist- Eric Ehlenberger
Colors Noble Gases
produce in lamp tubes:
• Ne (Neon): orange-red
• Hg (Mercury): light blue
• Ar (Argon): pale lavender
• He (Helium): pale peach
• Kr (Krypton): pale silver
• Xe (Xenon): pale, deep blue
Lanthanide Series
•Soft
•Malleable
•Shiny
•Very good conductors
•Used in industry
•Usually
form hard to separate
compounds
Actinide Series
•Only uranium and
thorium are found on
earth in significant
amounts.
•Elements after uranium
are man made and very
unstable