Download The Periodic Table

Organizing the Elements
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In the PT, elements are primarily organized by…
a. Atomic mass b. atomic number c. physical state
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Mendeleev and Meyer both developed early
PT’s organized by…
a. Atomic mass b. atomic number c. electron config
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Mosely reorganized the PT based upon…
a. Atomic mass b. atomic number c. electron config
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Three broad categories of elements include…
a. Metals
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b. non-metals c. metalloids
d. s, l, g
The Periodic Law states that chemical and
physical properties of the elements repeat
themselves in a regular way when organized
by increasing atomic number
a. True
b. False
In this section you will learn to
1. Explain how elements are organized in the
Periodic Table
2. Compare early and modern Periodic Tables
3. State the Periodic Law
4. Identify three broad classes of elements
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How do you organize a collection of different
things?
Elements are organized into groups based
upon their chemical properties
Elements that have similar chemical behavior
are grouped together
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Mendeleev is the father
of the modern periodic
table (1869)
Organized elements by
◦ increasing atomic mass
◦ Repeating pattern of
properties
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Was able to predict
unknown elements
using his table
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Reorganized periodic
table based upon
increasing atomic
number
Resolved
inconsistencies of
Mendeleev’s table
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When elements are arranged by increasing
atomic number….
Their physical and chemical properties repeat
in a periodic fashion (repeating pattern)
Properties of elements within a group are very
similar. Why?
Properties of elements vary in a regular way
across a period
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Most elements are metals (~ 80%)
Properties of metals
◦
◦
◦
◦
◦
◦
Solid at RT (except for Hg)
Good conductors of heat
Electrical conductivity
Luster
Ductile
Malleable
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Most nonmetals are gases at RT
Some solids, one liquid (Br)
Properties of Nonmetals
◦ Poor conductors of heat
◦ Poor electrical conductivity (except C)
◦ Brittle
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Metalloids sometimes called “semi-metals”
What does this tell you about metalloids?
Seven Metalloids
Properties of Metalloids
◦ Intermediate between metals and nonmetals
◦ Often depends upon conditions
◦ Example: Si is a poor electrical conductor, but is a
good conductor when mixed with small amounts of
boron.
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Mendeleev, the father of the PT, organized
the elements by ________________.
The modern PT is organized by _____________.
Three general categories or elements include
____________, ______________, and ___________.
The Periodic Law states that when elements
are organized by ________ _________ _______,
properties of the elements ___________ in a
_____________ way.
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Each square in the PT includes the ….
◦ a. Name b. symbol c. atomic number
mass e. all of these

d. atomic
All elements within a particular group
(column) of the PT have a common…
◦ a. physical state b. electron config

Representative elements include groups…
◦ a. 1-2 b. 13-18 c. IA – VIIIA d. all of these
In this section you will learn to
1. Describe information in the Periodic Table
2. Classify elements based upon electron
configuration
3. Distinguish representative elements from
transition metals
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Groups
◦ vertical columns
◦ 1-18
◦ IA – VIII A are
“representative elements”
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Periods
◦ horizontal rows
◦ 1-7
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Squares
◦ element symbol and other
information
◦ ~115
Inner Transition Metals
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Group 1:
Group 2:
Groups 3-12:
Group 17:
Group 18:
___________________?
___________________?
___________________?
___________________?
___________________?
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Elements are within a
group have the same
ending electron
configurations
This is why elements
within a group have
similar chemical
properties

Each square in the PT includes the ….
◦ a. Name b. symbol c. atomic number
mass e. all of these

d. atomic
All elements within a particular group
(column) of the PT have a common…
◦ a. physical state b. electron config

Representative elements include groups…
o
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a. 1-2 b. 13-18 c. IA – VIIIA d. all of these
The electron config for elements in group 16
end in
◦ a. s2
b. s2p2
c. s2p4
d. s2p6
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As you go across a period from left to right,
atomic size gets larger (True, False)
As you go down a group, atomic size gets
larger (True, False)
Ions are formed when atoms gain or lose
electrons (True, False)
Ionization energy is the energy required to
remove and electron from an atom (True,
False)
An atom with high electronegativity easily
gives up an electron (True, False)
In this section you will learn to
1. Describe trends among elements for atomic
size
2. Explain how ions are formed
3. Describe periodic trends for
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1. First ionization energy (IE1)
2. Ionic radius
3. Electronegativity
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Atomic Radius: half the distance between nuclei of
two like atoms joined together
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Increases from top to bottom down a group
Decreases from left to right across a period
Arrow points
toward increase
Atomic r (pm)
Ei1 (kJ/mol)
Electroneg
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Down a group, added energy levels increase
radius
Because atomic number increases across a
period, there is greater nuclear (+) charge
No energy levels are added across a period
This tends to draw electrons closer to
nucleus, decreasing atomic radius
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Atomic radius (increases/decreases) across a
period.
Atomic radius (increases/decreases) down a
group.
Atomic radius decreases across a period
because the nuclear attraction toward the
outer electrons is getting stronger (yes/no)
Atomic radius increases down a group
because the number of energy levels
increases (yes/no)
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In this section you will learn
What ions are and how they are formed
Determine the charge of an ion
Distinguish cations and anions
Describe the periodic trend for ionic radius
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Many reasons, but for one thing…
Ions are electrolytes, found in sports drinks
like Gatorade®
Your body’s nerves, brain, and muscles need
electrolytes to function properly
Muscle cramps occur when electrolytes are
depeleted
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Ions are atoms which have gained or lost
electrons
Cations are positively charged because they
have lost electrons (negative charges).
Anions are negatively charged because they
have gained electrons (negative charges).
Na0 → Na+ + eCl0 + e- → Cl-
6.3
Positive and negative ions form when
electrons are transferred between atoms.
6.3
Positive and negative ions form when
electrons are transferred between atoms.
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Cations and Anions
Cations are smaller
than their parent
atoms
Anions are larger
than their parent
atoms
Relative Sizes
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Ionic radius follows the same pattern as
atomic radius but remember…
Cations are smaller than their parent atoms
Anions are larger than their parent atoms
This is because of a change in the relative
strength of the nucleus, i.e….
◦ The ratio of protons to electrons changes
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In the case of cations, an energy level is lost
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An atom forms an ion when it (gains/loses)
electrons
At atom that has lost 3 e- has a charge of ___
and is a(n) (cation/anion)
Ca  ? + 2 eAn atom that has gained 2 e- has a charge of
___ and is a(n) (cation/anion).
Ionic radius (increases/decreases) across a
period and (increases/decreases) down a
group
The radius of a cation is (greater/smaller)
than its parent atom.
Atomic r (pm)
Ei1 (kJ/mol)
Electroneg
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Energy required to remove an e- from an
atom
Decreases from top to bottom down a group
Increases from left for right across a period
A0 + E i → A+ + e Na0 + Ei → Na+ + e-
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Energy required to remove 1st, 2nd, & 3rd eAl0 → Al+ + eAl+ → Al2+ + eAl2+ → Al 3+ e-
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Ei1= 578 kJ/mol
Ei2 = 1816 kJ/mol
Ei3 = 2744 kJ/mol
Why would it require more energy to remove
the 2nd electron?
The 3rd electron?
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Why are these important?
◦ These explain trends in atomic size, ionic size, and
ionization energy
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Nuclear charge
◦ tends to draw e-s toward nucleus (reducing atomic
radius)
◦ The bigger the atomic number, the more positive it is
◦ Increases across a period
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Electron Shielding:
◦ Inner (core) electrons “screen” outer electrons from
attractive force of the nucleus
◦ Allows outer e-s to move further from nucleus
(increasing atomic radius)
◦ Decreases down a group
◦ Does not change across a period
Atomic r (pm)
Ei1 (kJ/mol)
Electroneg
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Tendency of an atom to attract electrons to itself
when bonded to another atom
A very important property!
Electronegativity
4.5
Increases left to right across a period
Decreases down a group
4.0
3.5
Electronegativity
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0
10
20
30
40
50
Atomic Number
60
70
80
90
100