The Periodic Table
• Discovering the Elements Video:
• Introduction to Elements
• Dmitri Mendeleev’s Periodic Table of
Elements
• Henry Mosley’s Periodic Table of Elements
Dmitri Mendeleev
The Periodic Table
• Russian scientist Dmitri Mendeleev taught
chemistry in terms of properties.
• Wrote down the elements in order of
increasing mass.
• Found a pattern of repeating properties.
• Mendeleev created a periodic table by
grouping elements in columns by similar
properties in order of increasing atomic
mass.
• Moseley – changed the order to atomic
number
• Also found some gaps.
• Must be undiscovered elements.
• Predicted their properties before they were
found.
Modern Russian Table
Modern Russian Periodic Table
Chinese Periodic Table
Chinese Periodic Table
Stowe Periodic Table
A Spiral Periodic Table
TriangularPeriodic
Periodic Table
Table
Triangular
“Mayan”
Periodic
Table
Periodic Table with Group Names
Periodic Table with Group
Names
The Modern Periodic Table
• Elements are still grouped by properties.
• In order of increasing atomic number.
• Added a column of elements Mendeleev did
not know about.
• Horizontal rows are called periods.
• There are 7 periods.
• Vertical columns called groups.
• Elements are placed in columns by
similar properties.
• Also called families.
Elemental Information on the
Periodic Table
• Elements of Chemistry Video:
• Elements and Isotopes
• Ions
Reviewing the Structure of the Atom
• every atom consists of two regions:
1) nucleus = very small region located near the
centre of the atom.
• contains at least 1 positively charge particle called
a proton and usually 1+ neutral particles called
neutrons.
2) The area surrounding the nucleus is occupied by
negatively charged particles called electrons.
• This region is large (compared to the nucleus).
Elemental Information on the
Periodic Table
A
X
Z
X = element symbol
A = mass number
Z = atomic number
Atomic number (Z) = # of protons = # electrons
Mass number (A) = # of protons + # of neutrons
Isotopes
• The number of neutrons can vary in the
same element.
• This affects the weight of an atom, but
does very little to chemical and physical
properties.
• An isotope is the same element with a
different number of neutrons in the nucleus.
Ions
• Now, if there is a change in the electrons, the
atom becomes an ion.
•
Gaining electrons produces an anion (negative
ion)
• Losing electrons produces a cation
(positive ion)
• Charge symbols- if an element has a
charge the element will have either a
positive or negative # on the upper righthand corner.
Ie. Al3- & Ca2+
Metals, Metalloids, and NonMetals
Metals vs. Non-Metals
• Discovering the Elements Video:
• Metals and Non-Metals
Properties of Metals
• Metals are good
conductors of heat and
electricity
• Metals are malleable
• Metals are ductile
• Metals have high
tensile strength
• Metals have luster
Metal Artwork
of Regina,
Sask.
Examples of Metals
Potassium, K
reacts with
water and
must be
stored in
kerosene
Copper, Cu, is a relatively soft metal,
and a very good electrical conductor.
Zinc, Zn, is more
stable than
potassium
Mercury, Hg, is the only metal
that exists as a liquid at room
temperature
Properties of Nonmetals
Carbon, the graphite in“pencil lead” is
a great example of a nonmetallic element.
• Nonmetals are poor conductors of
heat and electricity.
• Nonmetals tend to be brittle.
• Many nonmetals are gases at room
temperature.
Examples of Nonmetals
Sulfur, S, was
once known as
“brimstone”
Graphite is not the only pure
form of carbon, C. Diamond is
also carbon; the color comes
from impurities caught within
the crystal structure
Microspheres of
phosphorus, P,
a reactive
nonmetal
Properties of Metalloids
• Metalloids straddle the
border between metals
and nonmetals on the
periodic table.
• They have properties of both metals and
nonmetals.
• Metalloids are more brittle than metals, less
brittle than most nonmetallic solids
• Metalloids are semiconductors of electricity.
• Some metalloids possess metallic luster.
Silicon, Si – A Metalloid
•
Silicon has metallic luster
• Silicon is brittle like a nonmetal
• Silicon is a semiconductor of
electricity
Other metalloids include:
• Boron, B
• Germanium, Ge
• Arsenic, As
• Antimony, Sb
• Tellurium, Te