3.3 METALS

Metals on the Periodic Table

Most metals are found to the left of the zigzag line on the periodic table

Physical Properties

Describe a metal.

Physical Properties

Most are hard Most are shiny Malleable

can be pounded into shapes Ductile

can be pulled out or drawn into a long wire

Good Conductions Transmit heat and electricity easily

Magnetic High Melting Point-most are solid

at room temperature

Chemical Properties

Metals show a wide range of chemical properties Some are very reactive such as

sodium and potassium. They will react if exposed to air or water so they must be stored under oil in sealed containers.

Other are unreactive such as gold and chromium. Gold is valued because its rare and it stays shiny because it does not react with the air. Chromium is plated on outdoor objects because it does not react with air or water.

Other elements fall inbetween gold and sodium in terms of reactivity. Iron will turn to rust if left to react with air and water. The rust can then wear away and flake off. The process of reaction and wearing away is called corrosion.

Alloys

Alloy-a mixture of metals Useful alloys combine the

best properties of two or more metals into a single substance Example: Copper is fairly

soft and malleable. But if you mix it with tin, it forms bronze which can be cast into statues that last hundreds of years.

Brass=Copper+Zinc Stainless

steel=Iron+carbon+cromium+vanadium (iron rust easily, stainless steel is used to make silverware)

Alkali Metals Group 1, 1 valence electron They are the most reactive metals They are never found uncombined in

nature (they are never found as elements, only as compounds)

Alkali metals are very soft and shiny-so soft you could cut them with a plastic knife

They are so reactive because they have only one valence electron. This is easily transferred to other atoms during a chemical change

The two most important alkali metals are sodium and potassium-your diet includes lots of both

Lithium compounds are used in batteries and some medicines

Alkaline Earth Metals

Group 2, 2 valence electrons Still highly reactive Never found uncombined in nature Fairly hard Bright white Good conductors of electricity The two most common are:

magnesium (once used in flash bulbs because gives off bright light when burned, combines with aluminum to make strong lightweight alloy used for ladders and airplane parts)

calcium (essential part of teeth, bones and muscles).

Transition Metals

Group 3-12 Form a bridge between the very

reactive metals on the left and the less reactive metals and other elements on the right

Very similar to each other, differences hard to detect

Familiar transition metals are: iron, copper, nickel, silver, gold

Hard, shiny Some have unusual colors Good conductors of electricity Stable, slow to react with air and

water

Metals in Mixed Groups

Groups 13-16 include metals, nonmetals and metalloids

Not very reactive metals in these groups

Popular metals in these groups: Aluminum-used to make beverage

cans and airplane bodies Tin- coats steel to protect it from

corrosion in cans of food Lead-auto batteries (previously

used in paint and pipes, but found to be poisonous)

Lanthanides and Actinides

At the bottom of the periodic table are the lanthanides (top row) and actinides (bottom row)

These are called the rare earth elements Lanthanides are soft, malleable, shiny metals with high

conductivity. They are used in industry to make various alloys. Lanthanides are found combined together in nature. They are difficult to separate because they are all so similar

Of the actinides, only thorium and uranium exist on Earth in any significant amounts. Uranium is used to produce energy in nuclear power plants. All the elements after uranium were created artificially in labs.

Vocabulary

Malleable Ductile Conductor Magnetic Corrosion Alkali metal Alkaline earth metal Transition metal Lanthanide actinide

Questions

List four properties of most metals Compare metals on the left side of the

periodic table to metals on the right. Describe three different types of metals