THE MODERN
PERIODIC TABLE
Mendeleev
 1834 - 1907
 1869 – Dmitri
Mendeleev
published the first
periodic table
Mendeleev
 Born in Siberia, the last
of 14-17 children
 Father blind, mother ran
glass factory
 When he finished high
school, his father died
and the factory burnt
down
Mendeleev
 His mother took
him to St.
Petersburg to study
science
 Denied admission
to the university, he
studied at a school
for teachers
Mendeleev
 In time, he became
a professor of
chemistry at the U.
of St. Petersburg
 While writing a
chemistry
textbook, he
developed the
periodic table
Mendeleev
 Where a gap existed in
his table, he predicted
a new element would
be found and deduced
its properties
 He was right. Three
elements were found
during his lifetime
 Ga, Sc, Ge
Mendeleev
 The discovered
elements provided the
strongest support for
his periodic table
 It is a cornerstone in
chemistry and in our
understanding of how
the universe is put
together
Mendeleev
 Mendeleev’s
table arranged
the elements in
order of
increasing
atomic mass
Modern Periodic Table
Modern Periodic Table
 Square of the periodic table contains an
element’s atomic #, chemical symbol,
atomic mass
Modern Periodic Table
 An element’s
properties can be
predicted from its
location in the
periodic table
 The elements in each
group have the same
number of valence
electrons
METALS
 Most elements are
metals
 88 elements to the
left of the
“staircase” are
metals or metal like
elements
Physical Properties
of Metals
 Luster (shininess)
 Good conductors of heat and
electricity
 High density (heavy for their size)
 High melting point
 Some metals (Fe, Co and Ni) are
magnetic
Physical Properties
of Metals
 Ductile (most metals can be drawn out
into thin wires)
 Malleable (most metals can be
hammered into thin sheets)
METALS
Chemical Properties
of Metals
 Metals show a wide
range of chemical
properties
 Reactivity – ease and
speed with which an
element combines, or
reacts with other
elements and
compounds
Chemical Properties
of Metals
 Some metals are
very reactive, some
do not react easily
 Alloy – mixture of
metals
 Examples: bronze,
brass, stainless
steel
Chemical Properties
of Metals
 Easily lose electrons
 Corrode easily. Corrosion is a gradual
wearing away
 Examples of corrosion: silver
tarnishing and iron rusting
Families of Metals

Group 1 – Alkali Metals

Group 1 – Alkali Metals
 Li
Na
 One valence
electron
 Most reactive
 Soft
 Low densities
 Low melting point
Group 1 – Alkali Metals
 Combine with
negative ions to
form salts
Group 1 – Alkali Metals

 Na, K
 Na compounds in
large amounts in
sea water
 Na and K both
essential for life
Group 1 – Alkali Metals
Group 2 – Alkaline Earth Metals
 Two valence
electrons
 Very reactive
Group 2 – Alkaline
Earth Metals
 Magnesium and
calcium are common
alkaline earth metals
 Calcium compounds
make up much of your
bones and teeth
Group 2 – Alkaline
Earth Metals
 Magnesium, when
combined with
aluminum, makes a
strong but
lightweight alloy
Group 2 – Alkaline Earth Metals


Transition Metals
Transition Metals
 Elements in Groups
3 – 12
 Bridge between very
reactive metals on
left side and less
reactive metals on
the right side
Transition Metals
 Transition metals
are fairly stable
 React slowly or not
at all
Rare Earth Metals
 Lanthanides and
Actinides
 Lanthanides are
soft, shiny metals
with high
conductivity
 Actinides are all
radioactive. Some
not found in nature
NONMETALS
 Nonmetals are found to the right of the
stair step line
 17 elements
 Make up most of the human body
Physical Properties of Nonmetals
 The physical properties of
nonmetals are opposite to
those of metals
Physical Properties
of Nonmetals





No luster (dull appearance)
Poor conductor of heat and electricity
Brittle (breaks easily)
Not ductile
Many are gases at room temperature
Physical Properties
of Nonmetals




Not malleable
Low density
Low melting point
Elements in this group have one
valence electron
 How does this affect their reactivity?
 It makes them VERY REACTIVE.
Chemical Properties
on Nonmetals
 Have many electrons in their highest
energy level
 Form negative ions
 Gain electrons
 Noble gases do not react with other
elements
Chemical Properties
of Nonmetals
 Diatomic molecule – when nonmetals form
molecules of two identical atoms
H H
METALLOIDS
 Elements that
border the zigzag
line have properties
of both metals and
nonmetals
 These elements are
called metalloids.
Physical Properties
of Metalloids





Solids
Can be shiny or dull
Ductile
Malleable
Conduct heat and electricity better
than nonmetals, but not as well as
metals
Physical Properties
of Metalloids
 Some are
semiconductors,
such as Si (silicon)
Boron Group
 Boron is the only
element in group 13
that is not a metal
 B is brittle, black
metalloid
 Al is the most
abundant metal in the
earth’s crust
 Aluminum has many
uses
Carbon Group
 Carbon is the only
nonmetal in Group
14
 Two common forms
– graphite and
diamond
 Each element has
four valence
electrons
Group 14 – Carbon Group
 Carbon is the
element essential
for life
 It is unique
because it can link
up with other C
atoms to form long
chains
Carbon Group
 Si and Ge are
metalloids
 Sn and Pb are
metals
Group 15 – Nitrogen Group




N and P are nonmetals
N makes up 80% of air
N is essential to life
N-fixing bacteria take
N from air and change
into compounds
plants can use
Group 15 – Nitrogen Group
 P (Phosphorus)
also necessary for
life
 P in bones, teeth
and DNA
 As and Sb are
metalloids
Group 16 – Oxygen Group
 O is the most
abundant element
on earth
 O is very reactive
and can combine
with almost every
other element
 S, Se are also
nonmetals
Group 17 -- Halogens
 Halogen means
“salt-former”
 Halogens combine
with metals to form
salts
 Have 7 valence
electrons
 F is the most
reactive nonmetal
Group 18 – The Noble
Gases
 Colorless gases
 Do not combine
with other elements
 Outer electron shell
is full
Group 18 – The Noble
Gases
 He is the second
lightest gas
Hydrogen
 H does not fit in
with any group
 Reacts easily with
other elements
 Can act like a metal
or a nonmetal
QUIZ YOURSELF!
 What are the rows
across the periodic
table called?
 Answer:
PERIODS
QUIZ YOURSELF!
 What is the term for
the vertical
columns in the
Periodic Table?
 Answer: Groups or
Families
QUIZ YOURSELF!
 How are the elements arranged in the
periodic table?
 In order of increasing atomic number
QUIZ YOURSELF!
 What is the most
reactive group of
metals?