Download groups - Northside Middle School

Group 1: Front
right of the
classroom
Adam
Brendan
Stephen
Sophie
Lilly
Alicia
Taylor V
Phoebe
Group 2: Desks
in the middle of
the room
Davis
Kyle
Haley
Chrissy
Eva
Emily
Tessa
Shannon
Group 3: Back of
The classroom
Nestor
Ben
Tyler
Christine
Brooke
Taylor W
Olivia
Castro
Smaller Groups
Group A:
Adam
Eva
Brooke
Group B:
Brendan
Haley
Christine
Group E:
Lilly
Davis
Taylor W
Group F:
Alicia
Kyle
Ben
Group C:
Stephen
Emily
Tyler
Group G:
Taylor V
Shannon
Olivia
Group D:
Sophie
Tessa
Nestor
Group H:
Phoebe
Chrissy
Castro
Do Now
• What do you think of when you hear the word
metal?
• What is a nonmetal?
• Do you know of any examples of each?
The Periodic Table consists of:
• METALS
• NONMETALS
• METALLOIDS
Properties of Metals
• Metals are good
conductors of heat and
electricity
• Metals are malleable
(can be hammered or
rolled into sheets)
• Metals are ductile (can
be made into wire)
• Metals have high
tensile strength
• Metals have luster
Examples of Metals
Potassium, K reacts with water
and must be stored in mineral oil
Copper, Cu, is a relatively soft
metal, and a very good electrical
conductor.
Examples of Metals
Zinc, Zn, is more stable than
potassium
Mercury, Hg, is the only metal
that exists as a liquid at room
temperature
Mixing metals
• Alloy = mixture of a metal with another
element, usually another metal
• Alloys have properties different from the
individual elements, usually eliminating some
disadvantages.
– Alloys are usually harder and more resistant to
corrosion
•
•
•
•
Ex: brass = copper + zinc
Ex: sterling sliver = copper + silver
Ex: steel = iron + carbon + manganese + nickel
Ex: Stainless steel = iron + chromium
Properties of Nonmetals
• Carbon, the graphite in “pencil lead” is a great
example of a nonmetallic element.
• Nonmetals are poor conductors of heat and
electricity
• Nonmetals tend to be brittle
• Many nonmetals are gases at room
temperature
Examples of Nonmetals
Sulfur, S, was once known as
“brimstone”
Microspheres of phosphorus, P, a
reactive nonmetal
Examples of Nonmetals
Graphite is not the only pure form
of carbon, C. Diamond is also
carbon; the color comes from
impurities caught within the crystal
structure
Bromine is a nonmetal that
exists as a liquid at room
temperature.
Properties of Metalloids
• Metalloids straddle the border between
metals and nonmetals on the periodic
table.
• They have properties of both metals and
nonmetals.
• Metalloids are more brittle than metals,
less brittle than most nonmetallic solids
• Metalloids are semiconductors of
electricity
• Some metalloids possess metallic luster
Silicon, Si – A Metalloid
Silicon has metallic luster
Silicon is brittle like a nonmetal
Silicon is a semiconductor of
electricity
Other metalloids include:
Boron, B
Germanium, Ge
Arsenic, As
Antimony, Sb
Tellurium, Te
Elements classified as metals and
nonmetals
http://www.ptable.com/
Do Now
• Take out your Reference Table and open to the
Periodic Table of Elements
• Do you notice any patterns as you look at the
properties of elements?
– Hints: scan left to right, and scan from the top
down
The Periodic Table
• PERIODIC LAW
– The physical and chemical properties of the
elements are periodic functions of their atomic
numbers (elements with similar properties appear
at regular intervals).
• THE MODERN PERIODIC TABLE
– An arrangement of the elements in order of
increasing atomic number so that the elements
with similar properties fall in the same column or
group.
Periodic Table with Group Names
PERIODS= Horizontal rows
GROUPS= vertical columns
VALENCE ELECTRONS
• Elements within the same group have the
same number of valence electrons.
VALENCE ELECTRONS
• Most loosely bound electron is called the VALENCE
ELECTRON!
• Valence electrons participate in chemical reactions,
so elements with similar valence electrons react in
similar ways.
• Noble gases are stable with 8 valence electrons.
• All elements with the exception of Hydrogen and
Helium want 8 valence electrons to be stable.
• Hydrogen and Helium want 2 valence electrons to be
stable.
GROUP 1
Alkali Metals
• Properties:
–
–
–
–
–
–
–
–
Metal
Easily lose valence electron
1 valence electron
Chemically reactive – do not
occur as free elements in
nature
Soft, silvery
Good conductor of electricity
React violently with water
React with halogens to form
salts
EXCEPTION:
Hydrogen is in group 1,
but has different properties than the alkali metals
Hydrogen
• Most common element in the universe.
• It consists of one proton and one electron.
• It can react with many other elements:
– With oxygen to make water
– With carbon to make organic compounds
– With nitrogen to make ammonia
GROUP 2
Alkaline Earth Metals
• Properties:
– They are metals, but
have less metallic
characteristics than
Alkali Metals
– 2 valence electrons
– Chemically reactive – do
not occur as free
elements in nature
– Harder, denser, stronger,
higher boiling points,
and slightly less reactive
than alkali metals
GROUP 17
Halogens (“Salt makers”)
• Properties:
– Most reactive nonmetals.
– 7 valence electrons – need
1 electron to become
stable
– They vigorously react with
metals to form salts.
•
•
•
•
F2 - most reactive element
Cl2
Br2
I2
GROUP 18
NOBLE GASES (or INERT GASES)
• Properties:
– Full set of valence electrons:
most elements have 8
valence electrons, except
Helium with 2 valence
electrons, but it is still
associated with this group
because its properties match
these elements.
– Extremely stable and occur as
monoatomic gases in nature
– Although they do not readily
combine with other
elements, but compounds of
Krypton and Xenon have been
prepared.
Monoatomic Atoms
• All of the noble gases are monatomic.
• Monatomic means it only contains one atom
of the element.
•
•
•
•
Transition Metals (d-Block)
They have “typical metallic properties”
Luster, ductile, malleable, good conductors of heat and electricity
Less reactive than Group 1 and 2
Many are unreactive (for example, palladium, platinum and gold are
found as pure elements in nature)
• As ions, the transition elements form colorful solutions.
• These elements begin in Period 4 and include Groups 3-12.
Lanthanides and Actinides (f-Block)
• Lanthanide Series- shiny metals similar in
reactivity to Alkaline Earth Metals
• Actinides Series- all radioactive (mostly
synthetic)
Magic seven
• Diatomic molecules= always exist as 2 of the
same atoms bonded to each other
H2
N2
O2
F2
Cl2
Br2
I2
Liquids on the Periodic Table
• There are 2 liquids on the periodic table at STP
• Mercury is the only metal that is a liquid
• Bromine is the only nonmetal that is a liquid
Allotropes
• An allotrope is the same element that can be
found in more than one different form
– Graphite and Diamond are allotropes of Carbon
– Dioxygen (O2)and Ozone are allotropes of Oxygen
Color-Code the Periodic Table
• You can use any colors you want, just make a key
on your personal periodic table
• On your personal periodic table color the
following, every bullet has to be a different color:
– Metalloids (on the staircase- 6 of them)
– The 2 liquids (Mercury and Bromine)
– The 7 Diatomics
– Noble Gases
– Transition Metals
– Color and Label groups 1,2,17, and 18 with the proper
name
Stephen
Eva
Christine
Tessa
Ben
Tyler
Castro
Brooke
Davis
Sophie
Brendan
Chrissy
Emily
Lilly
Alicia
Olivia
Kyle
Adam
Shannon
Taylor V
Phoebe
Taylor W
Haley
Nestor
Liquids on the Periodic Table
• There are 2 liquids on the periodic table at STP
• Mercury (Hg) is the only metal that is a liquid
• Bromine (Br) is the only nonmetal that is a
liquid
Allotropes
• An allotrope is the same element that can be
found in more than one different form
– Graphite and Diamond are allotropes of Carbon
– Dioxygen (O2)and Ozone are allotropes of Oxygen
Periodic Trends
•
•
•
•
•
•
•
ELECTRONEGATIVITY –Straws Lab
ATOMIC RADIUS- Pipe Cleaners/Bead
IONIC RADIUS
IONIZATION ENERGY- Straws Lab
ELECTRON AFFINITY
METALLIC CHARACTER
MELTING AND BOILING POINT
The trend depends on 3 factors:
1. NUCLEAR CHARGE= atomic number= # of
protons- the higher the nuclear charge the more
the electrons are pulled toward the nucleus.
2. PRINCIPAL ENERGY LEVEL- Principal energy level is
determined by the period an atom is located; the
higher the principal energy level, the higher the
potential energy, the larger the atom.
3. ELECTRON CLOUD SHIELDING EFFECT- inner
electrons shield the outer electrons so they are
less attracted to the nucleus so the atom is larger
Electronegativity
• A measure of the ability of an atom in a chemical
compound to attract electrons.
• FLUORINE is the most electronegative atom on the Periodic
Table
• PERIOD TREND: Electronegativity increases across a period
(the closer to 8 valence electrons the more they will pull on the
electrons)
• GROUP TREND: Electronegativity decreases down a group
(the larger the atomic radius the less ability of that atom to attract
electrons due to electron shielding)
Periodic Table of Electronegativities
Electronegativity Review
• Element with most Electronegativity:
• Fluorine (F)
• Element with least Electronegativity:
• Francium (Fr)
Atomic Radius
• Atomic radius = half of the distance between nuclei of
identical atoms bonded together (bond radius).
• This is determined by how strongly an atom’s nucleus
(positive charge) is attracted to its outermost electrons.
• PERIOD TREND: Radius decreases across a period
• Nuclear charge increases across a period so electrons are more
closely attracted to the nucleus
• GROUP TREND: Radius increases down a group
• Addition of principal energy levels, so inner electrons shield
outer electrons and the electrons are farther away from
nucleus, so atom is larger.
Table of Atomic Radii
Review Ions
• Ions are formed when atoms gain or lose
electrons
• Ions have a positive or negative charge
• Ionic Radii:
The loss or gain of electrons by an atom
causes a corresponding change in size.
Ionic Radii
Cations
• Positively charged ions
• Smaller than the
corresponding atom
• Metal tend to form CATIONS
by LOSING an electron.
• Metal cations are smaller
than their corresponding
neutral atoms (they lost
electrons).
Anions
• Negatively charged ions
• Larger than the
corresponding atom
• Nonmetals tend to for
ANIONS by GAINING an
electron.
• Nonmetal anions are larger
than neutral atoms because
they gained electrons.
Ionic Radius Review
• The loss or gain of electrons by an atom causing a
corresponding change in size.
Metals
• Tend to lose their valence electrons.
• What happens to their valence electrons? decrease
Before:
After:
• Therefore the atomic radius of metals is larger than their
ionic radius.
Ionic Radius Review
• The loss or gain of electrons by an atom causing a
corresponding change in size.
Nonmetals
• Tend to gain electrons.
• What happens to their radius? increases
Before:
After:
• Therefore the atomic radius of nonmetals is smaller than
their ionic radius.
Table of
Atomic
Radii
and
Ionic
Radii
Ionic Radius
Metals
form
CATIONS
Loss of electron
Get a Positive Charge
Nonmetals
Form
ANIONS
Gain of electron
Get a Negative charge
Radius Decreases
when it becomes an
ion
Radius Increases
when it becomes an
ion
Ionization Energy
• Ionization energy = the energy required to remove an
electron from an atom
A + ionization energy  A+ + e• PERIOD TREND: Tends to increase across a period
– Within same principle energy level: due to increased
nuclear charge the electrons are more closely attracted to
nucleus
• GROUP TREND: Tends to decrease down a group
– Addition of principle energy levels, so outer electrons are
farther from the nucleus due to electron shielding, so less
attracted to the nucleus
Ionization of Magnesium
• Ionization energy increases for successive electrons taken from
the same atom
Mg + 738 kJ  Mg+ + eMg+ + 1451 kJ  Mg2+ + eMg2+ + 7733 kJ  Mg3+ + e-
Ionization Energy Review
• Element with the most Ionization Energy:
• Helium (He)
• Element with the least Ionization Energy:
• Cesium (Cs)
• Why do noble gases have such high ionization
energy but no electronegativity?
Electron Affinity- Similar to
Electronegativity
• The energy change that occurs when an electron is
acquired by a neutral atom is called the atom’s
electron affinity.
A + e-  A- + energy
A + e- + energy  A- (unstable)
• PERIOD TREND: Tends to increases across a period
– due to increasing nuclear charge (remember: the Halogens
gain electrons most readily)
• GROUP TREND: Tends to decrease down a group
– due to increasing electron shielding from addition of
principle energy levels
REACTIVITY
• METALS- most reactive in lower left corner
• NONMETALS- most reactive in top right corner
Reactivity Review:
• Place the following elements in increasing
order of reactivity: (least reactive first)
– Sodium, potassium, calcium
Metallic Character
• As you go down a group, the metallic
character increases.
• As you go across a period, the metallic
character decreases. (Because they are nonmetals)
Summation of Periodic Trends- Add
them to your Periodic Table
Electronegativity
Electronegativity
Periodic Trends
Definition
Trend in Period
Electronegativity The measure of
Increases across
the ability of an
a period
atom in a
chemical
compound to
attract electrons
Trend in Group
Decrease down a
group
Atomic Radius
Half the distance Decreases across Increases down a
between nuclei
a period
group
of identical
atoms bonded
together
Ionization
Energy
The energy
required to
remove an
electron from an
atom
Increases across
a period
Decreases down
a group