Chapter 3- Understanding the 8th Grade Science Chapter 3- Understanding the Periodic Table © Fall 2005, Pflugerville ISD, 8th Grade

Why Do I Need the Periodic Table? What Do You Think? What similarities exist between you and the other members of your family? How about between you and your classmates? Unit A: Chapter 3

Periodic Table periods The periodic table is arranged by periods (rows) and groups/families. The reactivity of metals tends to decrease as you move from left to right across the periodic table Unit A: Chapter 3

Periodic Table Groups/Families A group is a vertical column in the periodic table Elements are grouped because they have similar properties Unit A: Chapter 3

Grouping the Elements - Group 1 Group 1: Alkali Metals- 1 Valence Electron All metals except Hydrogen, the Group 1 elements, are the most reactive. Metals are good conductors of heat and electricity Unit A: Chapter 3

Grouping the Elements - Group 1 Group 1: Alkali Metals- 1 Valence Electron Alkali metals react with other elements by losing one valence electron. Very Reactive Unit A: Chapter 3

Grouping the Elements - Group 1 Alkali Metals Compounds formed from Alkali metals have many uses for humans NaCl, or Sodium Chloride, is table salt that is used to season your food Potassium compounds are found in bananas Unit A: Chapter 3

Grouping the Elements - Group 2 Group 2: Alkaline-Earth Metals- 2 Valence Electrons Alkaline-Earth metals are very reactive, but not as reactive as Alkali metals. Unit A: Chapter 3

Grouping the Elements - Group 2 Group 2: Alkaline-Earth Metals- 2 Valence Electrons This is because it is harder for their atoms to lose 2 valence electrons than for the Alkali metals to lose 1 Unit A: Chapter 3

Grouping the Elements - Group 2 Group 2: Alkaline Earth Metals Magnesium is mixed with other metals to make rims on cars. Calcium is an important part of the compound that keeps your bones and teeth healthy. Unit A: Chapter 3

Grouping the Elements Groups 3-12 Groups 3-12 do not have individual names. They are called the Transition Metals Groups 3-12: Transition Metals Unit A: Chapter 3

Groups 3-12 The Transition Metals are less reactive than Groups 1 & 2 because they don’t lose their valence electrons as easily. Groups 3-12

Silver and Gold are Transition Metals. Grouping the Elements Silver and Gold are Transition Metals. Unit A: Chapter 3

Metalloid Metalloid have some characteristics of metals and nonmetals. Are semiconductors which means they can conduct electricity under some conditions but not others. Unit A: Chapter 3

Halogens are the very reactive nonmetals in Group 17. They react easily because their atoms only need to gain 1 electron to have a complete set Unit A: Chapter 3

Group 17 Chlorine is a yellow halogen that is used to disinfect water for drinking and swimming Unit A: Chapter 3

Noble gases are not reactive nonmetals in Group 18. These elements’ atoms have full outermost energy levels, and cannot react with other elements Unit A: Chapter 3

Noble gases like neon glow when electrically charged. Group 18 Noble gases like neon glow when electrically charged. Argon in a light bulb keeps the filament from burning out. Unit A: Chapter 3

Grouping the Elements Web Sites to Visit http://www.webelements.com/ http://chemlab.pc.maricopa.edu/periodic/periodic.html http://www.chemicalelements.com/ http://www.lenntech.com/periodic-chart.htm Unit A: Chapter 3

Let’s Review! 1 - How does the periodic table help you identify the physical properties of elements? Unit A: Chapter 3

How are elements grouped on the periodic table of elements? Let’s Review! 2 - How are elements grouped on the periodic table of elements? Unit A: Chapter 3