Chapter 12 Section 2 Grouping the Elements Bellringer How do you know that a bird is a bird, that a kangaroo is a kangaroo, and that a shark is a shark? What characteristics of each animal help you to tell the animals apart? How can such an analysis of characteristics be applied to elements?

Chapter 12 Section 2 Grouping the Elements Objectives Explain why elements in a group often have similar properties. Describe the properties of the elements in the groups of the periodic table.

Chapter 12 Group 1: Alkali Metals Section 2 Grouping the Elements Group 1: Alkali Metals Alkali metals are elements in Group 1 of the periodic table. Alkali metal properties: group contains metals 1 electron in the outer level very reactive softness, color of silver, shininess, low density

Group 2: Alkaline-Earth Metals Chapter 12 Section 2 Grouping the Elements Group 2: Alkaline-Earth Metals Alkaline-earth metals are elements in Group 2. Alkaline-earth metal properties: group contains metals 2 electrons in the outer level very reactive, but less reactive than alkali metals color of silver, higher densities than alkali metals

Group 3–12: Transition Metals Chapter 12 Section 2 Grouping the Elements Group 3–12: Transition Metals Transition metals are in Groups 3–12. Some of the transition metals are shown below.

Group 3–12: Transition Metals, continued Chapter 12 Section 2 Grouping the Elements Group 3–12: Transition Metals, continued Properties of Transition Metals vary widely but include: groups contains metals 1 or 2 electrons in the outer level less reactive than alkaline-earth metals shininess, good conductors of electric current and thermal energy

Group 3–12: Transition Metals, continued Chapter 12 Section 2 Grouping the Elements Group 3–12: Transition Metals, continued Lanthanides and Actinides Some transition metals from Periods 6 and 7 appear in two rows at the bottom of the periodic table. Elements in the first row are called lanthanides and elements in the second row are called actinides.

Chapter 12 Group 13: Boron Group Section 2 Grouping the Elements Group 13: Boron Group Aluminum is the most common element from Group 13. Group 13 properties: group contains one metalloid and five metals 3 electrons in the outer level reactive solids at room temperature

Chapter 12 Group 14: Carbon Group Group 14 properties: Section 2 Grouping the Elements Group 14: Carbon Group Group 14 properties: group contains one nonmetal, two metalloids, and two metals 4 electrons in the outer level reactivity varies among the elements solids at room temperature

Chapter 12 Group 15: Nitrogen Group Group 15 properties: Section 2 Grouping the Elements Group 15: Nitrogen Group Group 15 properties: group contains two nonmetals, two metalloids, and two metals 5 electrons in the outer level reactivity varies among the elements solids at room temperature (except for nitrogen, which is a gas)

Chapter 12 Group 16: Oxygen Group Group 16 properties: Section 2 Grouping the Elements Group 16: Oxygen Group Group 16 properties: group contains three nonmetals, one metalloids, and one metal 6 electrons in the outer level reactive solids at room temperature (except for oxygen, which is a gas)

Chapter 12 Group 17: Halogens Section 2 Grouping the Elements Group 17: Halogens Halogens are the elements in Group 17. Group 17 properties: group contains nonmetals 7 electrons in the outer level very reactive poor conductors of electric current, never in uncombined form in nature

Chapter 12 Group 18: Noble Gases Section 2 Grouping the Elements Group 18: Noble Gases Noble gases are the elements in Group 18. Group 18 properties: group contains nonmetals 8 electrons in the outer level (except helium, which has 2) unreactive colorless, odorless gases at room temperature

Chapter 12 Section 2 Grouping the Elements Hydrogen The properties of hydrogen do not match the properties of any single group, so hydrogen is set apart. a nonmetal 1 electron in the outer level reactive colorless, odorless gas at room temperature, low density