1. Representative Elements Chapter 5 Section 2

2. Representative Elements Remember that these are the elements in groups 1 and 2 and 13 to 18 Remember that these are the elements in groups 1 and 2 and 13 to 18 Groups are classified by having similar properties Groups are classified by having similar properties

3. Group 1 Alkali Metals Silvery Solids with low densities and low melting points Silvery Solids with low densities and low melting points Hydrogen is the only nonmetal in this group Hydrogen is the only nonmetal in this group Tend to increase reactivity down the family Tend to increase reactivity down the family –Lithium (Li) is the least reactive and Francium (Fr) is the most reactive –Contains Sodium (Na) and Potassium (K) too.

4. Group 2 Alkaline Earth Metals 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 Alkali metals Are reactive but not as reactive as Alkali metals –Contains Beryllium (Be), Magnesium (Mg), Calcium (Ca), Barium (Ba), Radium (Ra)

5. Group 13 Boron Family Are all metals except Boron Are all metals except Boron –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, and Baseball Bats

6. Group 14 Carbon Family A mixture of non-metals, metalloids and metals A mixture of non-metals, metalloids and metals Contains Carbon a non-metal Contains Carbon a non-metal Contains Silicon and Germanium Contains Silicon and Germanium Tin and Lead are the heaviest metals in this group Tin and Lead are the heaviest metals in this group Lead is used to shield humans during X- Rays Lead is used to shield humans during X- Rays

7. Group 15 The Nitrogen Group The top two elements are nitrogen and phosphorus, which are used by living things. The top two elements are nitrogen and phosphorus, which are used by living things. Our bodies need nitrogen, but cannot get it simply from breathing nitrogen from the atmosphere, bacteria in soil must first convert the nitrogen into a form we can use (The nitrogen cycle) Our bodies need nitrogen, but cannot get it simply from breathing nitrogen from the atmosphere, bacteria in soil must first convert the nitrogen into a form we can use (The nitrogen cycle)

8. Group 16 The Oxygen Family The oxygen group contains oxygen and sulfur which are essential for life and used to manufacture many products. The oxygen group contains oxygen and sulfur which are essential for life and used to manufacture many products. Sulfur is a solid, yellow nonmetal. Sulfur is used to manufacture sulfuric acid, which is used in fertilizers, detergents, synthetic fiber, and rubber. Sulfur is a solid, yellow nonmetal. Sulfur is used to manufacture sulfuric acid, which is used in fertilizers, detergents, synthetic fiber, and rubber.

9. Group 17 The Halogen Group All of the elements except Astatine are nonmetals. ‘ All of the elements except Astatine are nonmetals. ‘ The word Halogen means “salt former” for example: Table salt chemical make up is NaCl, you may have already noticed that chlorine is a halogen. All halogens form similar salts The word Halogen means “salt former” for example: Table salt chemical make up is NaCl, you may have already noticed that chlorine is a halogen. All halogens form similar salts Fluorine is most reactive, it combines with other elements easily. Chlorine is less reactive than fluorine but more reactive than bromine. Fluorine is most reactive, it combines with other elements easily. Chlorine is less reactive than fluorine but more reactive than bromine.

10. Group 18 The Noble Gases They rarely combine with other elements, they are chemically inactive They rarely combine with other elements, they are chemically inactive Helium is less dense than air so it is used in balloons. Hydrogen is also less dense, however Helium will not burn. Helium is less dense than air so it is used in balloons. Hydrogen is also less dense, however Helium will not burn. Noble gases glow different colors when electricity is passed through them. Neon lights are not necessarily just neon…unless of coarse they are reddish orange colored words. Noble gases glow different colors when electricity is passed through them. Neon lights are not necessarily just neon…unless of coarse they are reddish orange colored words. Helium, Argon, and Radon are all elements in this group Helium, Argon, and Radon are all elements in this group Why would you not expect to combine magnesium and argon to produce a useful substance? Why would you not expect to combine magnesium and argon to produce a useful substance?

11. An After thought…. What are the characteristics of two representative element groups? How are elements in these groups used. What are the characteristics of two representative element groups? How are elements in these groups used.