Transcript The Periodic Table of The Elements

The Periodic
Table of The
Elements
Periodic Table of Elements
• The structure and properties of atoms are
used to organize the periodic table, just as a
grocery store organizes food by its properties.
The Periodic Table
• Arrangement of the known elements based on
atomic number and chemical and physical
properties.
• Divided into three basic categories:
• Metals
• Nonmetals
• Metalloids
Basic Organization
The periodic table is organized by:
• Atomic Structure
• Atomic number
• Chemical and Physical Properties
Uses of The Periodic Table
The periodic table is useful in predicting:
• chemical behavior of the elements
• trends
• properties of the elements
Atomic Structure Review
• Atoms are made of protons, electrons, and
neutrons.
• Elements are atoms of only one type.
• Elements are identified by the atomic
number (# of protons in nucleus).
Energy Levels Review
• Electrons are arranged in a region around the
nucleus called an electron cloud. Energy
levels are located within the cloud.
• At least 1 energy level and as many as 7
energy levels exist in atoms.
Energy Levels Review
• Electrons in levels farther away from the
nucleus have more energy.
• Inner levels will fill first before outer levels.
Energy Levels & Valence Electrons
• Energy levels hold a specific amount of
electrons:
– 1st level = up to 2
– 2nd level = up to 8
– 3rd level = up to 8 (first 18 elements only)
Energy Levels & Valence Electrons
• The electrons in the outermost level are called
valence electrons.
– Determine reactivity - how elements will react with others
to form compounds
– Outermost level does not usually fill completely with
electrons
Using the Table to Identify Valence
Electrons
• Elements are grouped into vertical columns
because they have similar properties.
• These are called groups or families.
• Groups are numbered 1-18.
Using the Table to Identify Valence
Electrons
• Group numbers can help you determine the
number of valence electrons:
– Group 1 has 1 valence electron.
– Group 2 has 2 valence electrons.
– Groups 3–12 are transition metals and have 1 or 2
valence electrons.
Using the Table to Identify Valence
Electrons cont.
• Groups 13–18 have 10 fewer than the group
number. For example:
– Group 13 has 3 valence electrons.
– Group 15 has 5 valence electrons.
– Group 18 has 8 valence electrons.
Elements & Reactivity
• Reactivity is a chemical property that
determines how elements will react with
others to form compounds.
Elements & Reactivity
• What makes an element reactive?
● Number of valence electrons each atom has
● When outer levels are full, atoms are stable.
● When they are not full, they react:
● gain, lose, or share 1 or 2 electrons.
Elements & Reactivity
• The most reactive metals are the elements in
Groups 1 and 2.
– Elements in Group 1 need seven more electrons to fill their
outer level.
– Elements in Group 2 need six more electrons to fill their
outer level.
• These groups are known as the “givers”
because they easily give up their valence
electrons to make a compound.
Elements & Reactivity
• The most reactive nonmetals are the elements
in Groups 16 and 17.
– Elements in Group 16 only need two more electrons to fill
their outer level.
– Elements in Group 17 only need one more electron to fill
their outer level.
• These groups are known as the “takers”
because they easily receive valence electrons
to make a compound.
Groups
• Groups run vertically in the periodic table.
• They are numbered from 1–18.
• Elements in the same groups have the same
number of valence electrons in the outer
energy level.
• Grouped elements behave chemically in
similar ways.
Periods
• Periods run horizontally across the Periodic
Table
• Periods are numbered 1–7
• All the elements in a period will have the same
number of energy levels, which contain
electrons. Examples:
– Period 1 atoms have 1 energy level.
– Period 2 atoms have 2 energy levels.
– Period 5 atoms have 5 energy levels.
Periods Continued
• Moving from left to right across a period, each
element has one more electron in the outer
shell of its atom than the element before it.
• This leads to a fairly regular pattern of change in
the chemical behavior of the elements across a
period.
Group 1: Alkali Metals
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Contains: Metals
Valence Electrons: 1
Reactivity: Very Reactive
Properties:
– solids
– soft
– react violently with water
– shiny
– low density
Group 2: Alkaline-Earth Metals
• Contains: Metals
• Valence Electrons: 2
• Reactivity: very reactive, but less reactive than
alkali metals (Group 1)
• Properties:
– Solids
– Silver colored
– More dense than alkali metals
Groups 3-12 Transition Metals
• Contain: Metals
• Valence electrons: 1 or 2
• Reactivity: less reactive than alkali and
alkaline-earth metals
• Properties:
– Higher density
– Good conductors of heat and electricity
Groups 3-12 Transition Metals
Below Main Table
• Contain: The Lanthanide and Actinide Series
– These two rows are pulled out of sequence and
placed below the main table to keep the table
from being too wide.
– Lanthanides are #’s 58–71.
– Actinides are #’s 90–103.
Groups 3-12 Rare Earth Elements ~
Lanthanides
• Lanthanides follow the transition metal # 57
Lanthanum in Period 6.
• Valence electrons: 3
• Reactivity: Very reactive
• Properties:
● High luster, but tarnish easily
● High conductivity for electricity
● Very small differences between them
Groups 3-12 Rare Earth Elements ~
Actinides
• Actinides follow the transition metal # 89
Actinium in Period 7
• Valence electrons: 3 (but up to 6)
• Reactivity: unstable
– All are radioactive
– Most made in laboratories
Metalloids
• A zig-zag line that separates metals from
metalloids
• Elements from Groups 13–17 contain some
metalloids.
• These elements have characteristics of metals
and nonmetals.
Group 13: Boron Group
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Group 13: Boron Group
Contains: 1 metalloid and 4 metals
Valence Electrons: 3
Reactivity: Reactive
Other shared properties:
– Solid at room temperature
Group 14: Carbon Group
• Contains: 1 non-metal, 2 metalloids, and 3
metals
• Valence Electrons: 4
• Reactivity: Varies
• Other shared properties:
– Solid at room temperature
Group 15: Nitrogen Group
• Contains: 2 non-metals, 2 metalloids, and 1
metal
• Valence electrons: 5
• Reactivity: Varies
• Other shared properties:
– All but N are solid at room temperature
Group 16: Oxygen Group
• Contains: 3 non-metals, 1 metalloid, and 2
metals
• Valence Electrons: 6
• Reactivity: Reactive
• Other shared properties:
– All but O are solid at room temperature.
Groups 17 : Halogens
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Contain: Nonmetals
Valence Electrons: 7
Reactivity: Very reactive
Other shared properties
● Poor conductors of electric current
● React violently with alkali metals to form salts
● Never found uncombined in nature
Group 18 Noble Gases
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Contains: Nonmetals
Valence Electrons: 8 (2 for He)
Reactivity: Unreactive (least reactive group)
Other shared properties:
– Colorless, odorless gases at room temperature
– Outermost energy level full
– All found in atmosphere
Hydrogen Stands Apart
• H is set apart because its properties do not
match any single group.
• Valence electrons: 1
• Reactivity: very, but loses the 1 electron easily
• Properties:
– Similar to those of non-metals rather than metals
Properties of Metals,Metalloids and
Nonmetals
• Sheet of notebook paper.
• Fold into thirds.
• Label each column appropriately.
Henning Brand - 1649
Around 1669 he heated residues from boiled-down urine on
his furnace until the retort was red hot, where all of a
sudden glowing fumes filled it and liquid dripped out,
bursting into flames. He could catch the liquid in a jar and
cover it, where it solidified and continued to give off a palegreen glow. What he collected was phosphorus, which he
named from the Greek word for "light-bearing" or "lightbearer."
A. E. Beguyer de Chancoutois - 1817
French geologist and mineralogist who was the first to
arrange the chemical elements in order of atomic
weights.
Johann Dobereiner - 1862
Döbereiner discovered
trends in certain
properties of selected
groups of elements
These sets of elements became
known as "Dobereiner's Triads".
John Newlands - 1863
Law of Octaves
Lothar Meyer - 1864
known for the share he had in the
periodic classification of the elements
noted that if they are arranged in the
order of their atomic weights they fall into
groups in which similar chemical and
physical properties are repeated at
periodic intervals
Valence IV
Valence III
Valence II
Valence I
I line
Valence I
Valence II
The mass
difference
Li
Be
~16
II line
C
N
O
F
Na
Mg
~16
III line
Si
P
S
Cl
K
Ca
~45
As
Se
Br
Rb
Sr
~45
Te
I
Cs
Ba
~90
IV line
V line
Sn
Sb
VI line
Pb
Bi
Tl
~90
Dmitri Ivanovich Mendeleev - 1869
formulated the Periodic Law, created his
own version of the periodic table of
elements, and used it to correct the
properties of some already discovered
elements and also to predict the
properties of elements yet to be
discovered.
Lord Rayleigh - 1895
• discovered argon
Ernest Rutherford - 1911
he theorized that
atoms have their
charge concentrated in
a very small nucleus
Henry Moseley - 1913
• proposed that the atom contains in its nucleus
a number of positive nuclear charges that is
equal to its (atomic) number in the periodic
table
Glenn Seaborg - 1940
contributed to the discovery
and isolation of ten elements,
and developed the actinide
concept, which led to the
current arrangement of the
actinide series in the periodic
table of the elements
True or False
1. The following elements all belong to the same
period:
Ne, Ar, Kr, Xe
2. The following elements all belong to the
same group/family:
H, Li, Na, K
• 3. All elements in groups 13 have 3 valence
electrons.
• 4. The chemical reactivity of an element is
determined by its protons.
• 5. Mg is chemically similar to Ca.
Article Review
• As you are reading:
– Underline at least 4 statements of something you did not
know before reading.
– Circle at least 2 words you do not know the meaning of.
– Highlight the main ideas in the article: Who, what,
when, where and why
– Put a star * by something you read that you thought was
interesting.