Transcript Classroom Presentation

Physical Science Chapter 19
Elements and Their Properties
1
Let’s Review
Explain what your remember about how the
periodic table is organized.
Number the Groups and Periods
Where are the metals?
Where are the nonmetals?
Where are the metalloids?
• In the periodic table, metals are elements
found to the left of the stair-step line.
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19:1 Metals
Read Properties of Metals page 570.
A. Properties of metals
1. Conductive- Conduct heat and
electricity
2. Luster—reflect light well
3. Malleable— can be hammered
or rolled into sheets.
4. Ductile– can be drawn into
wires
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19:1 Metals
Read page 571-Ionic Bonding, Metallic
Bonding.
5. Ionic bonding—combine with
nonmetals by losing electrons
• When metals combine
with nonmetals, the
atoms of the metals
tend to lose electrons
to the atoms of
nonmetals, forming
ionic bonds.
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19:1 Metals
6. Metallic bonding —positively
charged metallic ions are
surrounded by a cloud of
electrons; ions are in sliding
layers and electrons are held
weakly. Readily form ionic
bonds with nonmetals.
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B. The Alkali Metals—softer and more
reactive than other metals
1. Highly reactive with
oxygen and water; don’t
occur naturally as
elemental forms
2. Combine readily with
other elements due to
single electron in outer
energy level
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3. Multiple uses
a. Human health —sodium,
potassium, and lithium
compounds
b. Photocells —some depend on
rubidium or cesium
c. Francium —a radioactive element
which breaks down giving off
particles and energy
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Alkali Metals
19:1
C. The Alkaline Earth Metals—
not found naturally in
elemental form; two electrons
in outer energy level
1. Applications— strontium and
magnesium found in
fireworks; magnesium in
vehicles, ladders and bats;
calcium in statues and
countertops
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19:1
2. Human body— calcium in bones;
barium in disease diagnoses;
radium formerly used in cancer
treatment
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Alkaline Earth Metals
19:1
D. Transition Elements —
often occur uncombined
in nature.
1. Typically form
colored
compounds—
chromium found in
rubies and emeralds
2. Iron triad— iron,
cobalt, and nickel
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19:1
Read page 574-5. Transition Elements.
a. Iron —most widely
used of all metals and
main ingredient in
steel; abundant in
Earth’s crust
b. Cobalt and nickel—
used in some steel
c. Nickel—used to coat
other metals
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Iron Mining 6.37
Iron Triad
19:1
Read page 574-5—Transition Elements
3. Copper, silver, gold—coinage
metals since once were
commonly used in coins
a. Copper—used in
electric wiring because
it is a superior
electricity conductor
b. Silver—used in
photographic film and
paper; jewelry
c. Gold—used in jewelry
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Coinage Metals
19:1
4.
Zinc, cadmium, mercury—
group 12 on periodic table
a.
b.
Zinc and cadmium—
often used to coat or
plate other metals
Mercury—only room
temperature liquid metal;
used in thermometers and
batteries
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Zinc Group
Read page 576- Inner Transition
Elements
E. Inner Transition Metals—seem
disconnected from rest of periodic table
1.
2.
The Lanthanides—include lanthanum,
cerium, praseodymium, samarium,
europium, gadolinium and terbium
The Actinides—all are radioactive and
unstable; uranium is the best known
• Metals in Earth’s
crust that
combined with
other elements
are found as ores.
• Most ores consist of
a metal compound,
or mineral, within a
mixture of clay or
rock.
Metals 6.31
Lanthanides and Actinides .57
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• Most of your
body’s mass
is made of
oxygen,
carbon,
hydrogen,
and nitrogen.
Calcium, a
metal, and
other
elements
make up the
remaining
four percent
of your
body’s mass.
19:2 Nonmetals
Read page 578- Properties of Nonmetals
A. Properties of nonmetals—usually gases or
brittle solids at room temperature; are not
malleable or ductile; usually poor
conductors of heat and electricity; usually
not lustrous.
1.
2.
Ionic compounds—form when nonmetals
gain electrons from metals and become
negative ions
Covalent compounds—form when
nonmetals share electrons with other
nonmetals
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19:2 Nonmetals
B.
Read page 579—Hydrogen
Hydrogen—most common element in universe
1.
2.
A diatomic molecule —two atoms of the same
element in covalent bond
Highly reactive element found mostly on
Earth as part of water compound.
1.
• Hydrogen can gain an
electron when it
combines with alkali
and alkaline earth
metals. These
compounds are called
hydrides.
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C. The Halogens—include
bromine, iodine, fluorine,
chlorine and astatine
1.
2.
3.
A salt forms when a halogen gains
one electron from a metal
Uses of halogens
a.
Chlorine—disinfectant and
bleach
b.
Bromine—dyes in cosmetics
c.
Iodine—hormone regulation
Sublimation—a solid changes
directly into a gas without first
becoming a liquid
The Halogens .44
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Halogens
D. Noble Gases—
exist as isolated,
stable atoms
1.
2.
Helium—used in
blimps and
balloons
Neon, argon and
krypton—used in
lights
Noble Gases .59
3
Noble Gases
19:3 Mixed Groups
A.
Read page 584—Mixed Groups—
Reading Guide-Properties of
Mettaloids.
Properties of Metalloids—form ionic and
covalent bonds; have some metallic and some
nonmetallic properties; partial conduction
gives them semiconductor characteristics
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B. The Boron Group—
named for the first
element in Group 13
1.
2.
Read page 584-Boron Group
Boron—used in
water softening
products,
antiseptics and
fuels
Aluminum—
abundant in Earth’s
crust; used in cans,
foil wrap, pans,
building materials,
and aircraft
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Boron Group
C.
Read page 585-Carbon Group
The Carbon Group—four
electrons in outer energy level
1. Carbon—found in coal, oil,
natural gas, foods.
2. Silicon occurs as an
allotrope—same element
with different molecular
structures
a.
b.
Silicon found in sand,
rocks, and soil
The main component in
semiconductors, which
conduct electricity under
certain conditions.
Carbon Group
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1.33
Carbon Group
19:3 Mixed Groups
c.
d.
e.
f.
Germanium—also used in semiconductors
Tin—used to coat other metals
Lead— toxic, so no longer used in paint
Diamonds, graphite and buckminsterfullerene
are all allotropes of carbon
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D.
The Nitrogen Group—five
electrons in outer energy
level; tend to form covalent
bonds
1. Nitrogen—used to make
nitrates and ammonia
2. Phosphorus—used in
water softeners,
fertilizers, match heads,
fire china
3. Antimony and
bismuth—used with
other metals to lower
their melting points Nitrogen Group 1.22
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Nitrogen Group
Circle Graphs
 Let’s look at Circle Graphs on page 587.
E. The Oxygen Group—Group 16
1. Oxygen—makes up 20% of
air, used by living things in
respiration, and provides
protection for Sun’s
radiation
2. Sulfur—used to form
sulfides for pigment in paint
3. Selenium—used in
photocopiers and
multivitamins
4. Tellurium and polonium are
also oxygen group elements
Oxygen Group .55
Oxygen Group
F.
Synthetic Elements—scientists create elements
not usually found on Earth; synthetic elements
usually disintegrate quickly
1.
2.
Uranium can be made into neptunium which
forms plutonium when it disintegrates
Plutonium can be changed into americium,
which is used in smoke detectors.
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3. Transuranium elements have
more than 92 protons and are
synthetic and unstable
a. The study of synthesized
elements helps scientists to
understand the forces holding
the nucleus together
b. Element 114 lasted for 30
seconds
c. It combined 114 protons with
175 neutrons
d. It broke apart due to
enormous repulsion between
the protons
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Why make elements?
• When these atoms disintegrate, they
are said to be radioactive.
• Radioactive elements can be useful.
For example, technetium’s radioactivity
makes it ideal for many medical
applications.
• In the 1960s, scientists theorized that stable
synthetic elements exist.
• Finding one might help scientists understand
how the forces inside the atom work.
Science and History
 The Gas that Glows—Neon. Read orally the
article on page 594.
Test coming soon.
Make sure your notes are complete and study them.
Homework is due on test day.