Download Periodic Table

Unit 4- The Periodic Table
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Alkali metals
Alkaline-earth metals
Alloy
Atomic radius
Bond radius
Electron shielding
Electronegativity
Family
Group
Halogen
Ionic radius
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Ionization energy
Main-group elements
Metal
Metalloid
Noble/inert gas
Nonmetal
Period
Periodic law
Transition metal
Valence electron
The elements of Earth’s crust
SUITS
NUMBERS
• Grouping the cards by suit and by number
reveals the missing card.
• Classification – grouping based on similarities
(just like we did with the playing cards)
• Consider a supermarket:
o All the dairy foods are in one
section.
o All the produce is in another
section.
• Grouping helps the shoppers to
find what they are looking for.
• Lets take a closer look at the dairy section.
Lactaid
Soy milk
Skim milk
Whole milk
• There are additional classifications within
the dairy section.
• Soy products can be in the produce section
too! Soy fits in two classifications at once!!
• Cross Classification - classifying into more than
one group at a time
• Examples
o Deck of cards
Suits and Numbers
o Periodic Table
Groups or Families and Periods
• What do the elements in a vertical column of
the Periodic Table have in common?
They have the same number of valence electrons.
• What do the elements in a horizontal row of
the Periodic Table have in common?
They have the same number of shells.
• Vertical columns
o Called groups or families.
o Have elements with similar arrangements of valence
electrons.
o Valence electron- electrons in the outermost shell of
an atom; determines atom’s chemical properties
• Horizontal rows
o Called periods.
o Have elements with the same number of shells.
• Dmitri Mendeleev (1869) prepared a card for
each of the known elements. He listed
o the symbol,
o the atomic mass,
o and the chemical properties.
• Mendeleev arranged the cards in order of
increasing atomic mass.
• He noticed a pattern.
• The properties repeated regularly.
• Mendeleev moved the cards, keeping them in
order of mass, so the first one with repeating
properties was under the one similar to it.
• The cards thus arranged formed groups or
families with similar properties.
• This arrangement forms the basis for the first
Periodic Table.
• Based on his observations, Mendeleev
concluded:
• This is known as the Periodic Law.
• Look through the Periodic Table. Are all the
elements in order with respect to mass? No
• Which elements are out of order with respect to
mass? Ar–K; Co–Ni; Te–I; Th–Pa; U–Np; Pu–Am
• Mendeleev was aware of some
of these discrepancies.
o He knew that if tellurium and iodine were
in the right family, they were out of
order with respect to mass.
o He believed that when scientists
improved techniques for measuring
atomic mass, these discrepancies
would disappear.
• Mendeleev found an important pattern −
repetition of properties. But does it make sense
to think that the pattern is caused by mass?
• What parts of an atom affect its mass?
protons and neutrons
• What parts of an atom affect its properties?
protons and electrons
• Today we know that different isotopes of the
same element have the same properties, but
have different masses because of neutrons which
affect the mass, but not the properties.
• Mendeleev does not make sense. Mass does not
cause chemical properties.
• When the elements were ordered so each was
in the correct family some were out of order
with respect to mass.
• When the elements are placed in the proper
order, they are numbered sequentially. This
number is called the atomic number.
• By using a technique called X-ray
diffraction, Henry Moseley (1913)
showed that the atomic number was
the nuclear charge or the number of
protons.
• Moseley showed that when the elements are
arranged in order of atomic number (as
measured by X-ray diffraction), the discrepancies
in Mendeleev’s Periodic Table disappear.
• Moseley corrected the Periodic Law:
• This is the basis for the modern Periodic Table.
• When Mendeleev
arranged the elements
in order of increasing
mass, he inadvertently
arranged them in order
of atomic number, with
few exceptions.
• The graph to the right
shows that there is a
direct relationship
between atomic mass
and atomic number.
• Each element has its own box on the Periodic Table with a lot of
information in it.
• There is a key to tell you what
information in each box means.
Although Periodic Tables differ,
most have the same basic
information.
• Starting from the top of the box,
the information on the key to the
right is as follows:
o [1] atomic mass - weighted average of the mass of the common isotopes of
the element;
o [2] common oxidation states - tells number of electrons lost, gained or shared
during bonding;
o [3] symbol - one, two, or three letters related to the name with the first letter
capitalized and other letters lower case. The three letter symbols are
systematic names that represent the atomic numbers of unnamed elements;
o [4] atomic number - number of protons; and
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o [5] electron configuration - arrangement of electrons in energy levels
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A Quick Tour of
The Periodic Table
Why is the Periodic Table important
to me?
• The periodic table is
the most useful tool
to a chemist.
• You get to use it on
every test.
• It organizes lots of
information about all
the known elements.
Groups…Here’s Where the Periodic
Table Gets Useful!!
• Elements in the
same group
have similar
chemical and
physical
properties!!
• (Mendeleev did that on
purpose.)
Why??
• They have the same
number of valence
electrons.
• They will form the same
kinds of ions.
Families on the Periodic Table
• Columns are also grouped
into families.
• Families may be one
column, or several
columns put together.
• Families have names
rather than numbers.
(Just like your family has a
common last name.)
Hydrogen- it’s own group
• Hydrogen belongs to a
family of its own.
• Hydrogen is a diatomic,
reactive gas.
• Hydrogen was involved in
the explosion of the
Hindenberg.
• Hydrogen is promising as
an alternative fuel source
for automobiles
Group 1- Alkali Metals
• 1st column on the
periodic table NOT
including hydrogen
• Very reactive metals,
always combined with
something else in
nature (like in salt).
• Soft enough to cut
with a butter knife
Group 2- Alkaline Earth Metals
• Second column on the
periodic table
• Reactive metals that are
always combined in
nature
• Several of these
elements are important
mineral nutrients (such
as Mg and Ca
Transition
Metals
• Elements in groups 3-12
• Less reactive harder
metals
• Includes metals used in
jewelry and
construction.
• Metals used “as metal.”
• Used to color paints
Group 13- Boron Family
• 3 valence electrons
• Aluminum metal was
once rare and
expensive, not a
“disposable metal”
• B is a metalloid all the
rest are metals
Group 14- Carbon Family
• 4 valence electrons
• Nonmetals, metalloids
and metals
• Contains elements
important to life and
computers.
• Silicon and
Germanium are
important
semiconductors
Group 15- Nitrogen Family
• 5 valence electrons, tend
to share when they are
bonded
• Nonmetals, metalloids
and metals
• Nitrogen makes up over
¾ of the atmosphere.
• Nitrogen and phosphorus
are both important in
living things.
• Most of the world’s
nitrogen is not available to
living things.
• The red stuff on the tip of
matches is phosphorus.
Group 16- Oxygen Family
• 6 valence electrons
• Oxygen is necessary
for respiration, most
abundant element of
Earth’s crust, reactive
and combines with
many other elements
• Many things that
stink, contain sulfur
(rotten eggs, garlic,
skunks,etc.)
Group 17- Halogens
• 7 valence electrons
• Very reactive, volatile,
diatomic, nonmetals
• Always found
combined with other
element in nature
• Used as disinfectants
and to strengthen
teeth.
Group 18- The Noble Gases
The Noble Gases
• Have a full valence
shell so…
• VERY unreactive,
monatomic gases
• Used in lighted “neon”
signs
• Used in blimps to fix
the Hindenberg
problem.
Periodic Table: Metallic arrangement
• Layout of the Periodic Table: Metals vs. nonmetals
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IA
1
18
VIIIA
2
IIA
13
IIIA
14
IVA
15
VA
16
VIA
17
VIIA
2
3
4
5
6
7
3
IIIB
4
IVB
5
VB
6
VIB
7
VIIB
8
9
VIIIB
Metals
10
11
IB
12
IIB
Nonmetals
Periodic Table: The three broad Classes
Main, Transition, Rare Earth
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Main (Representative), Transition metals, lanthanides and actinides (rare earth)
Reading the Periodic Table: Classification
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Nonmetals, Metals, Metalloids, Noble gases
Properties of Metals
• Conduct electricity and heat
• Lose valence electrons easily
• Malleable- can be pounded into
thin sheet
• Ductile- can be pulled into wire
• Low electronegativity
• Solid at room temp. (except Hg)
• Different metals can be mixed to
form an alloy
Properties of Nonmetals
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Poor conductor of heat and electricity
Brittle- if solid
Gain or share valence electrons easily
Nonductile
Solid, liquid or gas at room temp.
High electronegativity
Sulfur
Properties of
Metalloids or semi-metals
• Solids that can be dull or shiny
• Have characteristics of both
metals and nonmetals
• Ductile and malleable
• Conduct heat and electricity
better than nonmetals but not
as good as metals
• Useful in computer chip
material
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1
2
1
2
2
3
4
5
11
12
13
19
20
3
4
5
6
7
13
B
14
6
14
15
16
C
Si
Ge As
Sb Te
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7
8
9
10
15
16
17
18
• The number of protons increases.
• The pull on the electrons increases.
• Metallic properties decrease (except in the transition elements)
o Ionization energy increases.
• Ionization energy - energy needed to remove the most loosely held electron from
an element in the gaseous phase
• Found in Table S
o Electronegativity increases (also Table S).
o There is a gradual change from positive oxidation states to negative
oxidation states.
• The number of valence electrons increases.
• The number of shells remains the same.
• The number of protons increases.
• The number of shells increases.
• The atomic radius increases.
– Gets smaller across table due to more pull from
electrons on an increasingly positive nucleus
• The pull on the electrons decreases.
• Metallic properties increase.
• The number of valence electrons remains the
same.
Trend in Atomic Radius
•Atomic Radius:
•The size of at atomic specie as determine
by the boundaries of the valence e-.
Largest atomic species are those found in
the SW corner since these atoms have
the largest n, but the smallest Zeff.
Ionic Radius:
-radius of ions
-Follows the same trends as
atomic radius
Trend in Electronegativity
Electronegativity:
Discovered by Linus
Pauling
- A scale of numerical
values that reflect how
much an atom in a
molecule attracts
electrons
Trend in Ionization Energy
Ionization potential:
The energy required to remove the
valence electron from an atomic specie.
Largest toward NE corner of PT since
these atoms hold on to their valence ethe tightest.
Trend in Electron Affinity
Electron Affinity:
The energy change
that occurs when a
neutral atom gains an
electron. Most
favorable toward NE
corner of PT since
these atoms have a
great affinity for e-.
Summary of Trend
• Periodic Table and Periodic Trends
• 1. Electron Configuration
3. Ionization Energy: Largest toward NE of PT
4. Electron Affinity: Most favorable NE of PT
2. Atomic Radius: Largest toward SW corner of PT
Summary
• Periodic Table: Map of the Building block of matter
• Type: Metal, metalloid and Nonmetal
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Groupings: Representative or main, transition and
Lanthanide/Actanides
• Family: Elements in the same column have similar
chemical property because of similar valence electrons
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Alkali, Alkaline, halogens, noble gases
• Period: Elements in the same row have valence
electrons in the same shell.
• Table S--- a lot of information regarding each element!!