The Periodic Table of Elements
Historical Development of the
Periodic Table
•1790’s --- French scientist Antoine Lavoisier
compiled a list of elements known at the time.
• Many of the elements such as gold, carbon, and
oxygen were known since prehistoric times.
Historical Development of the
Periodic Table -- continued
•1864 ---John Newlands, an English chemist
proposed an organization scheme for the
known elements.
•He noticed that when elements were arranged
by atomic mass, their properties repeated
every eighth element. In other words, the first
and the eighth elements had similar properties.
Historical Development of the
Periodic Table -- continued
•1869 --- Lothen Meyer (a German chemist)
& Dimitri Mendeleev ( a Russian chemist)
organized elements by increasing atomic
mass into columns with similar properties,
which predicted the existence and properties
of undiscovered elements.
The Modern Periodic Table
Groups (sometimes called Families)
• are columns numbered from 1-8, followed by a letter
“A” or “B”.
•The groups designated with a letter “A” (1A to 8A)
are often referred as the main group or the
“REPRESENTATIVE ELEMENTS”.
•The groups designated with a “B” (1B through 8B)
are referred to as the “TRANSITION ELEMENTS”.
• A more recent numbering system, which uses the
numbers 1 through 18, also appears above each group.
The Modern Periodic Table --continued
Period ( rows on the periodic table)
The periodic table consists of rows called Periods
(There are a total of 7 rows or periods, beginning
with hydrogen)
•These rows also designate the energy level where
electrons are found (more about this when we talk
about electron configuration).
The Modern Periodic Table --Classifying the Elements
Metals --- elements that are generally shiny when
smooth and clean, solid at room temperature, good
conductors of heat and electricity.
• Most metals are ductile (drawn into wires) and malleable
(moldable).
Metals are
in green
The Modern Periodic Table --Classifying the Elements
Nonmetals --- elements that are generally gases or
brittle, dull-looking solids. They are poor conductors
of electricity.
•The only nonmetal that is a liquid at room
temperature is Bromine.
Non metals
are in
orange
The Modern Periodic Table --Classifying the Elements
Metalloids --- elements with physical and chemical
properties of both metals and nonmetals.
•Silicon and Germanium are two of the most important
metalloids, as they are used extensively in computer chips
and solar cells.
Metalloids
are in
purple
THE REPRESENTATIVE ELEMENTS
Group 1A – The Alkali Metals
• Elements in this family have 1
valence electron.
• Lose their valence electron to form a
+1 charged ion.
• Good conductors of heat and
electricity.
• Found combined with other elements
in nature due to their high reactivity.
• Soft enough to cut with a knife.
• Stored in oil to prevent a reaction
with oxygen in the air.
• Belong to the s-block in the periodic
table.
THE REPRESENTATIVE ELEMENTS
Group 2A – The Alkaline Earth
Metals
• Elements in this family have 2 valence
electrons.
• Lose their valence electrons to form a
+2 charged ion.
• Form compounds with oxygen called
oxides.
• Most compounds of alkaline earth
metals do not dissolve easily in water.
• Belong to the s-block in the periodic
table.
THE REPRESENTATIVE ELEMENTS
Group 3A – The Boron Group
• Is named for the metalloid Boron
• Elements in this family have 3
valence electrons
• Lose their valence electrons to form
a +3 charged ion.
• Most often found as oxides in the
earth’s crust
• Boron is the only metalloid in this
family, all other elements are metals
• Belong to the p-block in the
periodic table
THE REPRESENTATIVE ELEMENTS
Group 4A – The Carbon Group
• Is named for the nonmetal Carbon
• Elements in this family have 4 valence
electrons
• Lose their valence electrons to form a
+4 charged ion OR can gain 4
electrons and form a –4 charged ion.
• Contains one of the most important
elements on the periodic table, which
is carbon.
• Contains all three classifications:
carbon is a nonmetal, silicon and
germanium are metalloids, and tin and
lead are metals
• Belong to the p-block in the periodic
table.
THE REPRESENTATIVE ELEMENTS
Group 5A – The Nitrogen Group
• Is named for the nonmetal Nitrogen
• Elements in this family have 5 valence
electrons
• Gain 3 electrons to form a -3 charged ion.
Except Bismuth, which can lose 3
electrons and form ions with a +3 charge.
• About 78% of Earth’s atmosphere is
nitrogen; proteins and other essential
organic compounds contain nitrogen.
• Contains all three classifications: nitrogen
& phosphorus are nonmetals, arsenic &
antimony are metalloids, and bismuth is a
metal.
• Belong to the p-block in the periodic
table.
THE REPRESENTATIVE ELEMENTS
Group 6A – The Oxygen Group
• Is named for the nonmetal Oxygen.
• Elements in this family have 6 valence
electrons.
• Gain 2 electrons to form a -2 charged ion.
• Polonium is the most metallic member of
this family; it was discovered by Marie &
Pierre Curie and named after there native
land Poland; it is rare, radioactive &
extremely toxic.
• Contains all three classifications: oxygen
and sulfur are nonmetals, selenium &
tellurium are metalloids, and polonium is
a metal.
• Belong to the p-block in the periodic
table.
THE REPRESENTATIVE ELEMENTS
Group 7A – The Halogens
• Are named for their ability to form compounds
with all metals. Because these compounds are
called salts, Group 7A are called “salt formers,”
or Halogens
• Elements in this family have 7 valence
electrons.
• Gain 1 electron to form a -1 charged ion.
• Fluorine is a gas & the most reactive of all
halogens.
• Chlorine is a gas at room temperature.
• Bromine is a liquid, but evaporates easily.
• Iodine is a solid that an change directly into a
vapor.
• Astatine is radioactive with no known uses.
• Belong to the p-block in the periodic table.
THE REPRESENTATIVE ELEMENTS
Group 8A – The Noble Gases
• Were among the last naturally occurring
elements to be discovered because they are
colorless and unreactive.
• Elements in this family have 8 valence
electrons. This means they have the maximum
number of electrons in their outermost energy
level, 8, except for helium, which has two.
• Have no charge because they are stable.
• Nobles gases react rarely because of their stable
electron configuration. There are no known
compounds of helium, neon, & argon.
• In 1962, inorganic chemist, Neil Bartlett created
a compound of Xenon and Fluorine.
• Belong to the p-block in the periodic table.
THE TRANSITION METALS
Groups 1B- 8B (or more commonly referred to as
Groups 3-12)
• Conduct electricity & heat; have
luster, are malleable
• Most are hard solids with high
melting & boiling points.
• Transition metals can lose 2 s
electrons and form an ion with a
+2 charge
• Transition metals belong to the
• Because unpaired electrons can
d-block in the periodic table
move to the outer energy level,
• Metals such as iron, cobalt &
these elements can form ions with
nickel are said to be
a +3 charge or higher, as well.
ferromagnetic (which means
• Silver, gold, platinum & palladium
they are strongly attracted to a
are the only transition metals that
magnetic field.)
are unreactive enough to be found
• Belong to the d-block in the
in nature uncombined
periodic table
THE INNER TRANSITION
METALS -- The Lanthanide Series
(Period 6 on the Periodic Table)
• Silvery metals with relatively
high melting points.
• Because there is very little
variation in properties among the
inner transition metals, they are
found mixed together in nature
and are extremely difficult to
separate.
• Compounds of lanthanides are
used in movie projectors, lasers,
high-intensity search lights,
tinted sunglasses, welder’s
goggles, & in the steel industry to
remove carbon from iron.
• Oxides of some of these
metals are used in
television screens and
computer monitors
• Belong to the f-block in
the periodic table
THE INNER TRANSITION METALS
-- The Actinide Series
(Period 7 on the Periodic Table)
• Actinides are radioactive elements.
• Only 3 actinides exist in nature,
Thorium, Protactinium, &
Uranium.
• The rest are synthetic elements
called transuranium elements. A
transuranium element is an
elements whose atomic number is
greater than 92.
• Transuranium elements are created
in particle accelerators or nuclear
reactors.
• Most transuranium elements decay
quickly, except for plutonium-239,
which can remain radioactive for
thousands of years.
• Plutonium is used as fuel
in nuclear power plants.
• Americium is used for
home smoke detectors.
• Belong to the f-block in
the periodic table
NEWLY DISCOVERED ELEMENTS
-- Atomic Numbers 114, 116, & 118
• The names of these elements
are not officially assigned.
• Element with atomic # 114
currently goes by Ununquadium
and has a mass of 285 atomic
mass units.
• Element with atomic # 116
currently goes by Ununhexium
and has a mass of 289 atomic
mass units.
• Element with atomic # 118
currently goes by Ununodium
and has a mass of 293 atomic
mass units.