Transcript Two valence electrons.

PASS Content Standard 1.2
An element is composed of a single type of
atoms. When elements are listed in order
according to the number of protons
(called the atomic number), repeating
patterns of physical and chemical
properties identify families of elements
with similar properties.
Dmitri Mendeleev,
a Russian chemist
in the mid 1800s,
is known as
The Father
of the
Periodic
Table
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Mendeleev's Table - 3 min
Mendeleev arranged
elements by
increasing atomic
mass, leaving blank
spaces where he
was
sure
elements
Dmitri
yet
to
be
discovered
Mendeleev
would fit.
Fifty years after
Mendeleev, the
British scientist
Henry Moseley
discovered that
the number of
protons in the nucleus of a
particular type of atom was
always the same
When atoms were
arranged according
to increasing
atomic number,
the few problems
with Mendeleev's
table disappeared.
Because of
Moseley's work,
the modern
periodic table is
based on the
atomic numbers
of the elements.
The Periodic Law
states:
The physical and chemical
properties of the elements
are periodic functions of
their atomic numbers.
Vertical columns
are called
Groups or Families
Horizontal rows
are called
Periods
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Today's Table - 6 min
The 1 or 2 letter symbol.
The first letter is always
capital case, the
second letter is
always small case.
Many periodic tables do not
have the element name.
1 - Hydrogen
6 - Carbon
2 - Helium
7 - Nitrogen
3 - Lithium
8 - Oxygen
Many periodic tables do not
have the element name.
9 - Fluorine
12 - Magnesium
10 - Neon
13 - Aluminum
11 - Sodium
14 - Silicon
Many periodic tables do not
have the element name.
15 - Phosphorus
18 - Argon
16 - Sulfur
19 - Potassium
17 - Chlorine
20 - Calcium
Many periodic tables do not
have the element name.
24 - Chromium
27 - Cobalt
25 - Manganese
28 - Nickel
26 - Iron
29 - Copper
Many periodic tables do not
have the element name.
30 - Zinc
35 - Bromine
32 - Germanium
40 - Zirconium
33 - Arsenic
47 - Silver
Many periodic tables do not
have the element name.
50 - Tin
78 - Platinum
53 - Iodine
79 - Gold
74 - Tungston
80 - Mercury
Many periodic tables do not
have the element name.
82 - Lead
87 - Francium
86 - Radon
92 - Uranium
The whole number in
each square.
Indicates the number
of protons and the
number of electrons
in the atom.
This number is a decimal
fraction in most squares.
The total number of
protons and neutrons
in the atom.
Subtract the atomic number
from the mass
number to find
the number
of neutrons.
Our class wall table shows
man-made elements
with a white
chemical symbol,
all others
are natural.
Our class wall table shows
solids in black, liquids in
blue and gases in red.
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Metals & Nonmetals - 3 min
Families - vertical columns contain elements with similar
properties, usually
determined by the number
of valence electrons.
One valence electron.
The most active metals.
React with H2O to release
hydrogen gas.
Kept under oil.
Two valence electrons.
The second-most active metals.
Magnesium burns with
a very bright flame.
"Mag" wheels
Two valence electrons.
Commonly more than 1 oxidation #.
Form brightly colored compounds.
The "Precious" Metals
Two valence electrons.
Contains the Lanthanoid and
Actinoid series.
Their primary oxidation # is +3.
All actinoid elements are radioactive.
Three valence electrons.
Aluminum is the most
abundant metal and the
third most abundant
element in the
Earth's crust.
Four valence electrons.
Carbon's unique characteristic
of bonding to itself is responsible
for the complex molecules of life.
Silicon is the second
most abundant element
in the Earth's crust.
Diamonds
are pure carbon.
Five valence electrons.
Nitrogen is the most
abundant element in the
Earth's atmosphere. Phosphorus is a
key ingredient.
Six valence electrons.
Oxygen is the most abundant
element in the Earth's crust.
Oxygen supports combustion.
Sulfur
Seven valence electrons.
Halogens easily combine with
metals to form salts.
The most reactive of
all non-metals.
Iodine
Eight valence electrons.
Because of their electron arrangement,
they are almost completely inactive.
All are colorless gases.
Argon is the most abundant,
making up almost
one percent of
the atmosphere.
Elements with
properties of both
metals and nonmetals.
Metalloids touch the
metal-nonmetal line on
the periodic table.
Silicon and Germanium
are two metalloids
important in the
manufacture of
computer chips.
Their conducting
characteristics allow
electric circuits to be
"printed" on them.
The number of electron energy
levels is indicated by the
horizontal row on which
the element is located.
The shape of the table
shows the sublevels.
s
p
d
f
3
4
Energy Level Overlap
5
6
4
5
An orbital can hold 2 electrons.
Each orbital is represented by
two element squares on the table.
2
2
6
2
5
1s 2s 2p 3s 3p
Shows the location of
electrons in an atom.
2
2
6
2
5
1s 2s 2p 3s 3p
Chlorine
Large numbers show energy level.
Letters show sublevel.
Superscripts show the number
of electrons in the sublevel.
2
2
6
2
5
1s 2s 2p 3s 3p
Chlorine
Can be read directly
from the periodic table.
Think of each square on
the table as an electron.
Counting the squares will
give the number of
electrons in each
energy level and sublevel.
There are two ways
to check an
electron configuration
2
2
6
2
5
1s 2s 2p 3s 3p
Chlorine
1
The total of the subscripts
equals the atomic number
of the element.
2
2
6
2
5
1s 2s 2p 3s 3p
Chlorine
17
electrons
2
The last notation represents
the location of the element
on the periodic table.
2
2
6
2
5
1s 2s 2p 3s 3p
Chlorine
3rd row
p sublevel
5th element
End
Content
Standard 1.2