Representative Representative ElementsElements

Chapter 5 Section 2 Chapter 5 Section 2

Representative ElementsRepresentative Elements

Remember that these are the Remember that these are the elements in groups 1 and 2 and 13 to elements in groups 1 and 2 and 13 to 1818

Groups are classified by having Groups are classified by having similar properties similar properties

Group 1 Alkali MetalsGroup 1 Alkali Metals Silvery Solids with low densities and Silvery Solids with low densities and

low melting pointslow melting points Hydrogen is the only nonmetal in this Hydrogen is the only nonmetal in this

groupgroup Tend to increase reactivity down the Tend to increase reactivity down the

family family – Lithium (Li) is the least reactive and Lithium (Li) is the least reactive and

Francium (Fr) is the most reactiveFrancium (Fr) is the most reactive– Contains Sodium (Na) and Potassium (K) Contains Sodium (Na) and Potassium (K)

too. too.

Group 2 Alkaline Earth Group 2 Alkaline Earth MetalsMetals

Denser and Harder than Alkali Metals Denser and Harder than Alkali Metals Have higher melting points Have higher melting points Are reactive but not as reactive as Are reactive but not as reactive as

Alkali metals Alkali metals – Contains Beryllium (Be), Magnesium Contains Beryllium (Be), Magnesium

(Mg), Calcium (Ca), Barium (Ba), Radium (Mg), Calcium (Ca), Barium (Ba), Radium (Ra)(Ra)

Group 13 Boron Family Group 13 Boron Family

Are all metals except BoronAre all metals except Boron– Boron is a brittle, black metalloid Boron is a brittle, black metalloid

Used to make a variety of products Used to make a variety of products Such as Pots and Pans, Aluminum Cans, Such as Pots and Pans, Aluminum Cans,

and Baseball Bats and Baseball Bats

Group 14 Carbon FamilyGroup 14 Carbon Family

A mixture of non-metals, metalloids A mixture of non-metals, metalloids and metals and metals

Contains Carbon a non-metalContains Carbon a non-metal Contains Silicon and GermaniumContains Silicon and Germanium Tin and Lead are the heaviest metals Tin and Lead are the heaviest metals

in this groupin this group Lead is used to shield humans during Lead is used to shield humans during

X-Rays X-Rays

Group 15 The Nitrogen Group 15 The Nitrogen Group Group

The top two elements are nitrogen The top two elements are nitrogen and phosphorus, which are used by and phosphorus, which are used by living things. living things.

Our bodies need nitrogen, but cannot Our bodies need nitrogen, but cannot get it simply from breathing nitrogen get it simply from breathing nitrogen from the atmosphere, bacteria in soil from the atmosphere, bacteria in soil must first convert the nitrogen into a must first convert the nitrogen into a form we can use (The nitrogen cycle)form we can use (The nitrogen cycle)

Group 16 The Oxygen Group 16 The Oxygen FamilyFamily

The oxygen group contains oxygen The oxygen group contains oxygen and sulfur which are essential for life and sulfur which are essential for life and used to manufacture many and used to manufacture many products. products.

Sulfur is a solid, yellow nonmetal. Sulfur is a solid, yellow nonmetal. Sulfur is used to manufacture sulfuric Sulfur is used to manufacture sulfuric acid, which is used in fertilizers, acid, which is used in fertilizers, detergents, synthetic fiber, and detergents, synthetic fiber, and rubber. rubber.

Group 17 The Halogen Group 17 The Halogen GroupGroup

All of the elements except Astatine are All of the elements except Astatine are nonmetals. ‘nonmetals. ‘

The word Halogen means “salt former” for The word Halogen means “salt former” for example: Table salt chemical make up is example: Table salt chemical make up is NaCl, you may have already noticed that NaCl, you may have already noticed that chlorine is a halogen. All halogens form chlorine is a halogen. All halogens form similar saltssimilar salts

Fluorine is most reactive, it combines with Fluorine is most reactive, it combines with other elements easily. Chlorine is less other elements easily. Chlorine is less reactive than fluorine but more reactive than reactive than fluorine but more reactive than bromine. bromine.

Group 18 The Noble Gases Group 18 The Noble Gases They rarely combine with other elements, they They rarely combine with other elements, they

are chemically inactive are chemically inactive Helium is less dense than air so it is used in Helium is less dense than air so it is used in

balloons. Hydrogen is also less dense, however balloons. Hydrogen is also less dense, however Helium will not burn. Helium will not burn.

Noble gases glow different colors when Noble gases glow different colors when electricity is passed through them. Neon lights electricity is passed through them. Neon lights are not necessarily just neon…unless of coarse are not necessarily just neon…unless of coarse they are reddish orange colored words.they are reddish orange colored words.

Helium, Argon, and Radon are all elements in Helium, Argon, and Radon are all elements in this group this group

Why would you not expect to combine Why would you not expect to combine magnesium and argon to produce a useful magnesium and argon to produce a useful substance?substance?

An After thought….An After thought….

What are the characteristics of two What are the characteristics of two representative element groups? How representative element groups? How are elements in these groups used.are elements in these groups used.