GROUPING THE ELEMENTS

Chapter 5.2

Objectives:

1. Explain why elements in a group often have similar properties.

2. Describe the properties of the elements in the groups of the periodic table.

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•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•Transition metals are in Groups 3–12. Some of the transition metals are shown below.

Au Zn Cu Hg

Group 3–12: Transition Metals

•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

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.

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

B

AlGa

In

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

C

SiGe PbSn

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)

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)

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

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

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