Periodic Table

Periodic Table - 1 A periodic table is an arrangement of elements in which the elements are separated into groups according to their properties.

Periodic Table - 2 Each element is identified by its symbol placed in a square. The elements are listed in order of increasing atomic number, from left to right and top to bottom.

Periodic Table - 4 Each horizontal row of the periodic table is called a period. There are seven periods. Within the period the properties of the elements vary as you move across it from element to element.

Periodic Table - 5 Each vertical column of the periodic table is called a group, or family. Elements within a group have similar chemical and physical properties. There are 18 groups. Each group is identified by a number and letter A or B.

6.1 – Organizing Elements Dimitre Mendeleev (Russian Chemist) proposed a periodic table that could be used to predict the properties of undiscovered elements.

Periodic Table - 4 Each vertical column of the periodic table is called a group, or family. There are 18 groups, identified by a number and letter A or B. Elements within a group have similar chemical and physical properties.

Periodic Table - 3 The atomic number of the element is shown centered above the symbol. Hydrogen (H), the lightest element, is in the top left corner. Helium (He), atomic number 2, is the top right.

Example

Metals, Nonmetals, and Metalloids One way to classify elements in the periodic table is as metals, nonmetals, and metalloids (semi- metal). About 80% of elements are metals.

Characteristics of Metals Good conductors of heat and electricity Ductile, meaning can be drawn into wire. Malleable, meaning can be hammered into thin sheets without breaking. Shiny Examples: Na, Al, Cu, Mg

Characteristics of Nonmetals Poor conductors of heat and electricity. Brittle, meaning it will shatter if hammered. Not shiny Examples: Cl, F, N, O

Characteristics of Metalloids (semi- metal) Have properties similar to metal or nonmetal. Examples: silicon, As, Ge

Groups of Metal Four groups: Alkali metal – The members of group 1A. All are very reactive. Do not exist in free in nature. Example: Li, Na, K Rb, Cs, Fr.

Alkaline Earth Metals – Group 2A. Reactive metals but not as group 1A. Examples: Be, Mg, Ca, Sr, Ba, Ra

3. Transition Metals Groups 3 – 12 Moderate range of reactivity. Generally shiny and good conductors. Have higher densities and melting point than group 1 and 2.

Inner Transition Metals: The Lanthanides & Actinides Both placed at the bottom of the table. Lanthanides: Very similar to one another – soft and silvery. Very little commercial use. Some are used to produce color in color TV.

The Actinides All radioactive and are therefore unstable. Elements 95 through 103 do not exist in nature but manufactured in the lab by nuclear bombardment reaction.

The Boron Group (Group 13) – Most abundant metal. The Carbon Group (Group 14) – contains nonmetal, two metalloids, and two metals. The Nitrogen Group (Group 15) – contains two nonmetals, two metalloids, and one metal.

Oxygen Group (Group 16) – contains three nonmetals, one metalloids, and one metal. Halogens (Group 17) – All nonmetals. Very reactive. Poor conductors of heat and electricity. Tend to form salts with metals.

Noble Gases (Group 18) – Unreactive nonmetals. All are colorless, odorless gases at room temperature. All are found in earth’s atmosphere in small amounts.