The Periodic Table

Learning Objective Explain how elements are organized in the periodic table. Identify key features of the periodic table.

Interactive Notebook Use the notes on slides 4-9 to complete the notes on page 120 of your notebook.

Development of the Periodic Table In the 19th century, before much was understood about atomic structure, scientists used relative weight to order the known elements. Dmitri Mendeleev created an early version of the periodic table by arranging the 63 known elements by weight and grouping them by similar properties. Dmitri Mendeleev

Development of the Periodic Table Arranging the elements by mass resulted in several elements being placed in groups of elements with differing properties.

Development of the Periodic Table Henry Mosley arranged elements in order of increasing atomic number. arranging elements in order of increasing atomic number = no more problems with the order of the elements in the periodic table

Development of the Periodic Table Mosley’s arrangement of the elements by atomic number resulted in a clear periodic pattern of properties. The periodic law states that when elements are arranged in order of increasing atomic number, elements with similar properties occur at periodic (regularly recurring) intervals.

The Modern Periodic Table The modern periodic table consists of boxes, each containing an element name, symbol, atomic mass, and atomic number.

The Modern Periodic Table The boxes are arranged in order of increasing atomic number into a series of columns, called groups or families, and rows, called periods.

Number the groups as shown below on the periodic table on page 121.

Number the periods as shown below on the periodic table on page 121. What about these elements? What periods are they in?

Actual Periodic Table Shape The two rows at the bottom actually fit right here.

Learning Check Give the symbol of the element that occupies each of the following positions in the periodic table. – Period 4, Group 2 – Period 5, Group 6 – Group 1, Period 2 – Group 14, Period 5

Interactive Notebook Cut out the Metals, Nonmetals, and Metalloids periodic table and paste it to page 122. Cut out the Properties of Metals, Nonmetals, and Metalloids graphic organizer and paste it to page 123.

Classification of the Elements One of the most common ways to classify the elements is by using physical properties. – Using this method, elements are described as metals, nonmetals, or metalloids. The majority of the elements are metals. Only 22 elements are nonmetals. The step-like heavy line that runs through the right third of the periodic table separates the metals on the left from the nonmetals on the right.

Metals, Nonmetals, and Metalloids Draw a dark line on the periodic table on page 122 to indicate the separation between metals and non-metals.

Color code the metals, nonmetals, and metalloids on your periodic table The elements in the green boxes bordering the stair step line are called metalloids, or semimetals. Be Sure to make a Key

Interactive Notebook Use the information on the next three slides to fill in the graphic organizer on page 123.

Metals generally shiny when smooth and clean Mostly solid at room temperature good conductors of heat and electricity malleable (can be pounded into thin sheets) ductile (can be drawn into wires).

Nonmetals generally gases or brittle, dull-looking solids poor conductors of electricity and heat good heat insulator no luster (not shiny) brittle in solid state non-ductile

Metalloids have physical and chemical properties of both metals and nonmetals found on the “stupid stairs” “Boron the Moron” is at the top of the “stupid stairs”

Learning Check In which of the following pairs of elements are both members of the pair metals? – Cl and Br – Cu and Mo – Al and Si – Zn and Bi

Interactive Notebook Color and label the periodic table on page 121 using the directions on the next slides.

Classification of the Elements Elements are also classified based on the electron configuration of the elements, in which elements are described as noble-gas, representative, transition, or inner transition elements.

Groups 1 and 2 and are called the representative elements. Choose a color and color all of the representative (main-group) elements.

The elements in groups 3-12 are referred to as the transition elements. Choose a color and color all of the transition elements.

The two sets of elements at the bottom of the periodic table are called inner-transition elements. These are further divided into lanthanides and actinides. Choose a color and color all of the inner transition elements.

Interactive Notebook Somewhere on page 121, draw a key for the colors you used for the representative, transition, and inner-transition elements. representative elements (groups 1,2 and transition elements (groups 3-12) inner transition elements (lanthanides and actinides)

Group 1 (except for hydrogen) are known as alkali metals Outline the alkali metals with a dark green colored pencil or highlighter and write “alkali metals” above that row. Alkali metals

Group 2 – alkaline earth metals Outline the alkaline Earth metals with a light green colored pencil and write “alkaline Earth metals” above that row. Alkaline Earth metals Alkaline Earth metals

Group 17 – halogens Outline the halogens with a yellow colored pencil or highlighter and write “halogens” above that row. halogens

Group 18 – noble gases Outline the noble gases with a red colored pencil and write “noble gases” above that row. Noble gases

Homework Attach Periodic Table Review to page 124 in your notebook. Complete this worksheet for homework. I will check this worksheet on Monday.