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Elements and Compounds
Lesson 2: What Are Metals?
San Francisco’s City Hall DomeThe dome on San
Francisco’s City Hall is 307.5 feet high. This is 14 inches higher than the done of the Capitol Building in Washington, D.C. The dome was refinished when its old finish peeled off. Gold leaf was applied over a special paint to protect it.
California State Standards:
1.c) Students know metals have properties in common, such as high electrical and thermal conductivity. Some metals, such as aluminum (Al), iron (Fe), nickel (Ni), copper (Cu), silver (Ag), and gold (Au), are pure elements; others, such as steel and brass, are composed of a combination of elemental metals.
1.e) Students know scientists have developed instruments that can create discrete images of atoms and molecules that show that the atoms and molecules often occur in well-ordered arrays.
Valuable Vocabulary
Metal- A substance that transfers heat and electricity well and is malleable.
Valuable Vocabulary
Nonmetal- a substance that does not transfer heat and electricity well and is not malleable.
The prefix non- means “not.”
Valuable Vocabulary
Malleable- easy to shape or to form. Malleable is derived from the Latin term malleus meaning “hammer.”
Valuable Vocabulary
Metalloid- A substance that has some of the properties of a metal and some of the properties of a nonmetal.
Valuable Vocabulary
Alloy- a solid solution made by combining metals or a metal and nonmetal.
Metals and Nonmetals Metals conduct heat and electricity well
and are malleable whereas nonmetals do not conduct heat and electricity well.
Metals and Nonmetals Imagine you are at a park on a hot, summer day.
You notice a tall, metal slide positioned next the
swings.
Would you go down the slide? Why or why not?
Metals and NonmetalsSome people would not go down the metal slide
because it was probably too hot due to the sunlight.
A metal is a substance that is a good conductor of heat and electricity.
Metals heat up quickly, and electricity passes through them easily.
Metals and Nonmetals About 75% of the elements on the periodic table are
metals. Metals are located on the left side, with the exception of
hydrogen, and the middle of the periodic table.
Metals and NonmetalsHydrogen and the elements found on the right side
of the periodic table are nonmetals.Nonmetals are substances that do not have the
same properties as metals.They do not conduct heat and electricity well.
Example: Plastic
Metals and NonmetalsOn a hot, summer day a metal slide feels much
hotter than a plastic slide.
Plastic- a substance made of nonmetals- does not
conduct heat or electricity very well.
Metals and NonmetalsMost metals are silver or gray in color.
Some substances pretend to look like a metal.
These substances are called metallic- they reflect
light and are often shiny.
Examples: Gold, silver, and new pennies.
Metals and Nonmetals
Metals and NonmetalsOther than being good conductors of heat and
electricity, metals are malleable.
They are easy to shape or form; they can be
hammered or rolled into very thin sheets.
The San Francisco City Hall dome is less than one
millimeter thick!
Metals and NonmetalsWe all use metals in our daily lives!
Gold was most likely the first metal used by
humans because it does not rust and is often
found in nature as a pure element.
As we learned to work with metals, other forms of
technology improved as well.
Metals and Nonmetals
Show What You KnowHow can you tell if a substance is a metal?
Show What You Know How can you tell if a substance is a metal?
Metals conduct heat and electricity well. They are malleable and reflect light.
Show What You KnowWhere are metals and nonmetals found on the periodic table?
Show What You KnowWhere are metals and nonmetals found on the periodic table?
Metals are found on the left side and middle of the periodic table. Nonmetals are found on the right side of the periodic table.
Show What You KnowWhat does the term “malleable” mean?
Show What You KnowWhat does the term “malleable” mean?
Malleable means easy to shape or form.
Summary Time!Write a summary about what you learned today.
Be sure to:Use complete sentencesUse proper punctuationAnswer in paragraph form
Properties of Metals Metals have the same properties: they
conduct heat and electricity well, they are malleable, and they have melting and boiling points.
Properties of MetalsThink about each column in the periodic table.
What do we know about these columns?
Properties of Metals
Properties of MetalsWe know that all elements in the same column of
the periodic table have similar physical properties.
Each column is known as a “family.”
Like a real family, these elements are related.
For example, lithium and other metals in the first column are the most active metals.
Properties of MetalsAnother physical
property of metals include their melting and boiling points.
Properties of MetalsAnother physical
property of metals include their melting and boiling points
For example, when mercury is heated or cooled, it expands or shrinks evenly.
Properties of Metals Metals are in our every day lives!
Since metals are good conductors of heat, many cooking pans are made of metal.
They have a high thermal conductivity.
The handles of pans are covered with plastic or wood because nonmetals do not conduct heat very well.
Properties of Metals Another important use of metals is in electrical wiring.
On the outside of a cord of an appliance, there is rubber or plastic.
Inside the cord is a metal wire, usually copper.
Copper allows electricity to pass through easily, meaning they have high electrical conductivity.
Properties of Metals The rubber or plastic on the cord of the appliance
is known as an insulator.
Materials that do not conduct electricity or heat well are called insulators.
They prevent us from getting shocked!
Properties of Metals Different metals have different densities.
Aluminum and titanium are less dense than others, therefore, they are very light.
These metals are often used in airplanes and other objects in which weight is important.
Show What You Know Explain how the columns in the periodic table are related?
Show What You Know Explain how the columns in the periodic table are related?
The columns in the periodic table have similar physical properties.
Show What You Know What elements have properties similar to those of the element calcium?
Show What You KnowWhat elements have properties similar to those of the element calcium?
The elements that have similar properties to calcium are berylium, magnesium, strontium, barium, and radium.
Show What You Know What properties do aluminum, iron, and copper have in common?
Show What You Know What properties do aluminum, iron, and copper have in common?
Aluminum, iron, and copper all conduct heat and electricity and are malleable.
Show What You KnowWhat are some physical properties of metals?
Show What You KnowWhat are some physical properties of metals?
Some physical properties of metals are their melting and boiling points, malleability, and conductivity of heat and electricity.
Show What You KnowWhat is the material that does not conduct electricity or heat called?
Show What You KnowWhat is the material that does not conduct electricity or heat called?
The material that does not conduct electricity or heat is called an insulator.
Show What You Know How do the properties of metals affect the ways they are used?
Show What You KnowHow do the properties of metals affect the ways they are used?
Metals are used in pans because they are good conductors of heat. They are used in wires because they conduct electricity. They can be shaped in different objects. The less dense metals are used in airplanes.
Summary Time!Write a summary about what you learned today.
Be sure to:Use complete sentencesUse proper punctuationAnswer in paragraph form
Alloys and Metalloids The properties needed for a
particular use of an alloy determine the elements that go into it.
Alloys and MetalloidsAs we learned in the previous sections, we use
metals in our everyday lives.
Imagine you are sitting at the dinner table, eating a big, juicy steak, steamy mashed potatoes, and a fresh, green salad.
When eating this delicious meal, you would use forks or spoons made of stainless steel.
Alloys and MetalloidsThe stainless steel that is used to make the forks
and spoons is an alloy.
An alloy is a solid solution made by combining metals or a metal with a nonmetal.
The word alloy comes from the Latin word ad, meaning “to” and ligare, meaning “to bind.” Put together, the words mean “to bind to.”
Alloys and MetalloidsAn alloy contains properties that are different from
the elements that the alloy contains.
For example, iron is the main metal in many steel alloys.
Iron is not very hard, but when it is made into steel by adding carbon, it becomes much stronger.
Alloys and Metalloids There are many different forms of steel.
High-carbon steel is strong and flexible, which is why it is used for wire springs.
Low-carbon steel can be formed into shapes, such as gas tanks.
Alloys and MetalloidsStainless steel does not rust, and it will not
combine with the chemicals in food.
There are some stainless steels that do not contain iron. You can use a magnet to see if your forks and spoons contain iron.
Alloys and MetalloidsThe first alloys made were different kinds of
bronze.
Bronze is made by combing tin and copper, which is harder, stronger, and less likely to corrode than copper.
Corrode means “to break materials down by combining with things like oxygen.”
Alloys and MetalloidsMany large statues are made out of bronze
because they can withstand harsh weather conditions without corroding.
Ship propellers are made of bronze because it resists corrosion by sea water.
Another form of bronze contains aluminum that does not cause sparks when it is hit.
Alloys and Metalloids
Alloys and Metalloids Another type of element on the periodic table is the
metalloids.
Metalloids are elements that have some properties of metals and some of nonmetals.
The suffix –oid means “like” or “resembling.”
They are also called semimetals.
Alloys and MetalloidsAn example of a metalloid is silicon- it looks shiny,
but it isn’t as strong as a metal.
It breaks down when you hit it with a hammer.
It conducts electricity, but not as well as copper or silver, so the flow of electricity can be easily controlled.
Alloys and Metalloids Elements that can conduct electricity but can be easily
controlled are called semiconductors.
These elements are used in computers and portable devices such as music players.
Show What You KnowIn your own words, explain what an alloy is.
Show What You KnowIn your own words, explain what an alloy is.
An alloy is a solid solution that is made by combining either metal with metal or metals with nonmetals.
Show What You KnowIf an alloy is a solution of a solid dissolved in a solid, how might you make such a solution?
Show What You KnowIf an alloy is a solution of a solid dissolved in a solid, how might you make such a solution?
Melt the two solids and mix them together. Then let the solution cool off to get a solid again.
Show What You KnowWhat is the advantage of adding carbon to iron?
Show What You Know What is the advantage of adding carbon to iron?
It makes the resulting steel stronger.
Show What You KnowIf you were building a large statue of your face that was going to be placed outside, in your front yard, which alloy would you use- bronze or copper? Why?
Show What You KnowIf you were building a large statue of your face that was going to be placed outside, in your front yard, which alloy would you use- bronze or copper? Why?
If you were going to make a statue of your face, you would want to use bronze because it resists corrosion and is much harder and stronger than copper.
Summary TimeWrite a summary about what you learned today.
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Seeing Metal Atoms By understanding how atoms join
together, it helps scientists develop new materials and control the properties of these materials.
Seeing Metal Atoms As we learned in lesson 1, atoms are extremely
small.
If you joined 20 million large atoms placed side by side, it would only measure one centimeter.
So how can scientists see something so small?
Seeing Metal Atoms In the 1930s, scientists built an electron
microscope that could magnify an object more than 50,000 times.
This microscope used a stream of electrons to produce images of objects.
They could see objects, such as parts of cells, in great detail.
Seeing Metal Atoms Only 50 years later, in
1980, a new type of microscope gave scientists the capability to look at atoms.
A scanning tunneling microscope, or STM, uses a probe to examine the surface of a material.
Seeing Metal AtomsThe STM produces an image based on how many
electrons move from each part of the surface to the probe.
They could see atoms in
solids that were arranged
in specific patterns.
Seeing Metal Atoms With an STM, scientists can watch atoms form
natural crystals and arrays.
An array is a pattern of atoms.
Sometimes, there are missing pieces or flaws in these well-ordered arrays.
Seeing Metal Atoms
Seeing Metal AtomsThis technology may become very helpful to
people.
Today, scientists can check
materials for flaws before the
materials are used.
Seeing Metal AtomsScientists can also use STMs to observe
molecules.
By doing so, they learn why certain elements will and will not join together.
This understanding helps improve all kinds of electronic devices.
Show What You KnowWhy do scientists want to be able to see atoms?
Show What You KnowWhy do scientists want to be able to see atoms?
By understanding how atoms join together, scientists are able to develop new materials and control the properties of materials.
Show What You Know Why would scientists want to be able to move atoms around?
Show What You KnowWhy would scientists want to be able to move atoms around?
Scientists would want to be able to move atoms in hopes to make new materials.
Show What You Know What would you look for if you were looking for a flaw using an STM?
Show What You Know What would you look for if you were looking for a flaw using an STM?
If you were looking for a flaw using an STM, you would look for missing atoms, atoms that looked different from the others, or atoms that weren’t lined up like the rest.
Summary Time!Write a summary about what you learned today.
Be sure to:Use complete sentencesUse proper punctuationAnswer in paragraph form
