Download The Periodic Table

The Periodic Table
Chapter 6
Date: 1/ 6/ 2014
Bell Ringer
Explain how items in a
grocery store are organized.
Describe the characteristics
that might be used to group
produce in a store. Be
specific!

6.1
Searching For an Organizing
Principle
How did chemists begin to organize the
known elements?
Chemists used the properties of
elements to sort them into groups.
6.1
Searching For an Organizing
Principle

Chlorine, bromine, and iodine have very similar
chemical properties.
Recall: What are
chemical
properties?
-Heat of
Combustion
-Reactivity with
water
Recall: What are
physical
properties?
-Melting point
-Freezing point
-Color
-pH
-Smell
(the breaking of
bonds in reactants,
the forming of bonds
in products)
-Density
People and Periodic Table
Dmitri Mendeleev
 Credited with organization of FIRST
periodic table

Elements were arranged by
increasing atomic mass.

Elements were listed in columns so
that those with similar properties were
side by side.

He predicted the existence and
properties of new elements (blank
spaces in the first periodic table).
6.1
Mendeleev’s Periodic Table

An Early Version of Mendeleev’s Periodic Table
People and Periodic Table
Henry Moseley
 The
discovery of isotopes made it
apparent that atomic mass was not
the significant player in periodic law
 Moseley
used X-rays to determine
the atomic number of the known
elements and then arranged the
elements according to increasing
atomic number.
 Because
of Moseley's work, the
modern periodic table is based on
the atomic numbers of the
elements.
Summary of Periodic Table Research

Mendeleev - The properties of the
elements are a periodic function of their
atomic masses.

Moseley - The properties of the elements
are a periodic function of their atomic
numbers.
6.1
The Periodic Law
In the modern periodic table, elements
are arranged in order of increasing
atomic number.
6.1
The Periodic Law
Periodic law - When elements are arranged in order of
increasing atomic number, there is a periodic repetition of
their physical and chemical properties.

 The
properties of the elements within a period change
as you move across a period from left to right.
 The
pattern of properties within a period repeats as you
move from one period to the next.
Periodic Law

Called a “Periodic Table” because many of the
physical and chemical properties of the elements
repeat in a systematic manner with increasing
atomic number.
 Periods
are the horizontal rows in the table.
 Groups
are the vertical columns
Electron Location

Kernel of an atom is the nucleus and all the electrons
except the valence electrons.
Groups

The elements are arranged vertically in columns of the
P.T. called Groups or FAMILIES.
 Group
 These
# indicates the number of valence electrons.
electrons influence the chemical and physical
properties of elements the most.
Electron Location
Periods

The elements are arranged horizontally in rows of the
P.T. called Periods.
 Each
period # represents an energy level. Thus
locating an element identifies the number of occupied
energy levels.
Summary




Elements are arranged by increasing atomic
number across the periodic table.
Periods are the horizontal rows.
The period # = # of principle energy levels
Elements are grouped vertically by similar
chemical and physical properties.
Groups (or Families) are the vertical columns.
The group # = # of valence electrons.
What are three broad classes of elements?
Three classes of elements are metals, nonmetals,
and metalloids.

Across a period, the properties of elements
become less metallic and more nonmetallic.
Metals, Nonmetals, and
Metalloids
 Uses of Iron, Copper, and Aluminum
Metals, Nonmetals, and
Metalloids
 Uses of Iron, Copper, and Aluminum
Metals, Nonmetals, and
Metalloids
 Uses of Iron, Copper, and Aluminum
Metallic Characteristics









80% of elements are metals
Conduct electricity and heat
Dense
Malleable (bendable to form shapes – jewelry)
Ductile (able to be drawn out into wires)
Lustrous (shiny)
Reactive
High Melting point
Solid at RT
Metals

Good conductors of heat and electric
current.

80% of elements are metals.
 Metals have a high luster, are ductile, and
are malleable.
 Prefer to form cations – loss of electrons to
obtain a full valance shell
Non-Metals





Poor conductors of heat and electricity
In solid form, they are dull and brittle
Usually have lower densities than metals
Many nonmetals (hydrogen, nitrogen, oxygen,
fluorine, chlorine, bromine, and iodine) are
diatomic, and most of the rest are polyatomic
Prefer to form anions - gaining electrons to achieve
an octet.
Metalloids
3A





Share properties with both Less
metallic
metals and nonmetals
metalloid
Solids
Semi-conductors (between a
conductor and an insulator)
Form cations or anions. # of
valence electrons varies.
The behavior of a metalloid
can be controlled by
changing conditions.
3A
4A 5A
Poor
Metals
6A
7A
More
metallic
metalloid
Were You Paying Attention?
1.
The modern periodic table has elements
arranged in order of
a. colors.
b. melting and boiling points.
c. increasing atomic mass.
d. increasing atomic number.
Were You Paying Attention?
2.
Mendeleev arranged the elements in his
periodic table in order of increasing
a. atomic number.
b. number of protons.
c. number of electrons.
d. atomic mass
Were You Paying Attention?
3.
Which one of the following is NOT a
general property of metals?
a. ductility
b. malleability
c. having a high luster
d. poor conductor of heat and electricity
Squares in the Periodic Table
What type of information can be displayed in
a periodic table?
The periodic table displays the symbols and names
of the elements, along with information about the
structure of their atoms.
6.2
Squares in the Periodic Table
Representative Elements
Transition Elements
Alkali Metals






The alkali metals are silvercolored
Soft solids (Fr and Cs are liquids)
Group number:
React readily with halogens
React readily with water
One valence electron
 so they want to lose an electron
and achieve a noble
configuration (which is?)
 form +1 cations
Alkaline Earth Metals






Silvery colored
Soft solids
Group number:
React readily with Group 6
React readily with water (though
not as rapidly as the alkali
metals)
Two valence electron
 so they want to lose 2
electrons and achieve a noble
configuration (an octet)
 form +2 cations
Transition Metals






Often form colored compounds.
They are often good catalysts
 lowers activation energy so
rxns are faster
 not used up in the rxn
They are silvery-blue at room
temperature (except copper
and gold) - lustrous.
Malleable
They are solids at room
temperature (except Hg)
Good conductors of electricity
(Why?)
Lanthanide




Silvery-white metals
that tarnish when
exposed to air
Relatively soft metals
Very reactive
Many rare earth
compounds fluoresce
strongly under
ultraviolet light
Actinide




All are radioactive
The metals tarnish
readily in air
Actinides are very
dense metals
Actinides combine
directly with most
nonmetals
Diatomics

Diatomic elements are nonmetal elements that
form a covalent bond between two atoms.

“Diatomic 7”

As elements they always travel in pairs of atoms
and therefore you must write then as:

H2, N2, O2, F2, Cl2, Br2, I2
Halogens




Group number:
Highly reactive
 Due to atoms being one electron
short of a full outer shell.
 Form -1 anions.
 Fluorine is the most reactive
element in existence
Form diatomic molecules (F2, Cl2, Br2,
I2)
All three states of matter are
represented
 fluorine and chlorine are gases
 bromine is a liquid
 iodine and astatine are solids
Noble Gases
or Inert Gases



Group number:
Odorless, colorless, monatomic
gases.
Stable or unreactive
 They have the maximum
number of valence electrons
their outer shell can hold.
Electron Configurations in
Groups

Eddie
Electrons determine properties of elements
Elements can be sorted into noble gases,
representative elements, transition metals,
or inner transition metals based on their
electron configurations.
Electron Configurations
in Groups

The Noble Gases
 Noble gases - elements in Group 8A of the
periodic table.
2
2–8
2–8–8
2 – 8 – 18 – 8
Electron Configurations in
Groups
The Representative Elements
 Elements in groups 1A through 7A
 Display a wide range of physical and chemical
properties.
 The s and p sublevels of the highest occupied energy
level are not filled.
 The group number equals the number of electrons in
the highest occupied energy level.
Electron Configurations in
Groups

In atoms of the Group 4A elements below, there
are four electrons in the highest occupied
energy level.
Transition Elements
2 Types
(classified based on their electron configurations)
Transition Metals
• Group B
•Highest occupied s
sublevel
• Characterized by
presence of electrons in
d orbitals.
Inner Transition Metals
• Lanthanides & actinides
• Highest occupied s
sublevel
• Characterized by
presence of electrons in f
orbitals
Organization of Elements by
Electron Configurations


Pattern of blocks
Organized by highest occupied sublevels.
Practice
Electron Configurations in Groups
Group 4A
Carbon (C)
Silicon (Si)
Germanium (Ge)
Group 1A
Hydrogen (H)
Lithium (Li)
Sodium (Na)
Potassium (K)
Were You Paying Attention?
1.
Which of the following information about
elements is usually NOT included in a
periodic table?
a.
color
b.
symbol
c.
atomic number
d.
atomic mass
Were You Paying Attention?
2.
An alkali metal would have in the highest
occupied energy level
a.
an s2 electron.
b.
an s1 electron.
c.
p2 electrons.
d.
p6 electrons.
Were You Paying Attention?
3.
Which one of the following is incorrectly
labeled?
a. Ne, noble gas
b. Cu, transition metal
c. Ga, transition metal
d. Cl, halogen
Were You Paying Attention?
4.
Transition metals are characterized as being
different than representative elements because
they have electrons in which suborbitals?
a)
p
b)
d
c)
s
d)
f
Periodic Trends
Atomic radii/ Atomic Size
 Ions
 Ionization energy
 Ionic size
 Electronegativity

Trends in Atomic Size
Atomic radius is one half of the distance
between the nuclei of two atoms of the same
element when the atoms are joined.

Trends in Atomic Size
What are the trends among the elements for
atomic size?
Atomic size increases from top to bottom
within a group and decreases from left to right
across a period.
Increases
Decreases
Trends in Atomic
Size
Group Trends in Atomic Size
Drawing
Conclusions
: of
Based
on the
data for
Predicting:
Is
an
atom
barium,
atomic
Analyzing Data: Which alkali metal has an
alkali
metals
and noble
gases,than
howan
does
number
56,
smaller
or
larger
atom of
atomic radius of 238 pm?
atomic
change within a group?
cesiumsize
(Cs)?
Periodic Trends in Atomic Size

Complete practice problems #30-33.
6.3
Ions
Ion - an atom or group of atoms that has a
positive or negative charge.
How do ions form?
Positive and negative ions form when
electrons are transferred between atoms.
6.3
Ions
“CAT EYE”
Formation of a Cation
 Loss of e-’s
 Assume a more “+” charge
 Typically metals
6.3
Ions
Formation of an Anion
 Gain of e-’s
 Assume a more “-” charge
 Typically Nonmetals
6.3
Trends in Ionization Energy
Ionization energy – the energy required to
remove an electron from an atom.
First ionization energy tends to
decreases from top to bottom
within a group and increases left to
right across a period.
First Ionization Energy??
6.3
Trends in Ionization Energy
The energy required to remove an electron from an
ion with a 1+ charge is called the second ionization
energy.

• Removing e-’s from
the outer energy level/
shell First
• E’s in the outer shells
are less strongly held
by the nucleus
• E’s in the outer shell
require less energy to
remove then those at
lower energy levels
Prediction:
Drawing
Analyzing
Conclusions:
IfData:
you drew
Which
a
What
graph
element
is the
forinsecond
group
periodtrend
2 has
forthe
ionization
first
lowest
ionization
first
energy,
ionization
energy
which
for
energy?
element
noble gases
Inwould
period
and
you
3?alkali
have to
omit?
metals?
Explain.
Trends in Ionization Energy
6.3
Trends in Ionic Size
Trends
in Ionic Size
Metals form
 Nonmetals form
Cations
 are always smaller than the atoms
from which they form. Anions are always
larger than the atoms from which they form.

6.3
Trends in Ionic Size

Relative Sizes of Some Atoms and Ions
Size generally increases
6.3
Trends in Ionic Size
6.3
Trends in Electronegativity
Electronegativity - the ability of an atom of an element
to attract electrons when the atom is in a compound.
In general, electronegativity values decrease
from top to bottom within a group. For
representative elements, the values tend to
increase from left to right across a period.
Metals have low electronegativity values; more likely to
lose e-’s & become a cation
 Nonmetals have higher electronegativity values; more
likely to gain e-’s & become anions

6.3
Decreases
Trends in Electronegativity

Answer Practice Problems #40-45 in note
packet
Summary of Trends
Increases Decreases
Size
Electronegativity
Ionic
Atomic
Nuclear
Shielding
Ionization
of
size
cations
Size
anions
Charge
energy
Increases
Decreases
Constant
Were You Paying Attention?
1.
Which of the following sequences is correct for
atomic size?
a. Mg > Al > S
b. Li > Na > K
c. F > N > B
d. F > Cl > Br
Were You Paying Attention?
2.
Metals tend to
a. gain electrons to form cations.
b. gain electrons to form anions.
c. lose electrons to form anions.
d. lose electrons to form cations.
Were You Paying Attention?
3.
Which of the following is the most
electronegative?
a. Cl
b. Se
c. Na
d. I

SOL Review - 16 Questions