The Periodic Table - Winston-Salem/Forsyth County Schools

The Periodic Table What Does Periodic Mean? Periodic means repeated in a pattern Think about a calendar: Weeks are periodic they repeat every 7 days

Dimitri Mendeleev (1834 - 1907) Created the first way to organize all known elements Based

his table on the pattern of chemical properties Mendeleevs Periodic Table Based on

chemical properties Organized by atomic masses Predicted

unknown elements Henry Moseley (1887 1915) His work led to a reorganization of

Mendeleevs table by atomic number Killed by a sniper in World War One at age 27 The Modern Periodic Table Organized

into Rows = Periods Columns = Families Periods and Families The

families are numbered at the top of your periodic table in your reference table Take a pen and number the periods Number one is the row with Hydrogen Number seven is the row with Francium Names of Families

Group 1A or 1 Alkali Metals Names of Families Group 2A or 2

Alkaline Earth Metals Names of Families Group 7A or 17

Halogens Names of Families Group 8A or 18 Noble Gasses

Special Groups Groups 3-12 Transition Metals Special Groups 1st Row at Bottom

Lanthanoids OR Lanthanides Special Groups 2nd Row at Bottom Actinoids OR

Actinides One Other Feature Notice the dark stairstep line. Separates metals

from nonmetals Metals To the left of the stair-step line Typically solids with high melting points

Good conductors of heat and electricity Malleable can be formed into a different shape Ductile can be drawn into wires Metals As

you move left across the periodic table, metals become more reactive As you move down a group (family), metals become more reactive Remember the video about cesium? Where are the most reactive elements on the periodic table? Metalloids

Touching the stair-step line Have properties in between metals and nonmetals Semiconductors Think silicon in computer chips Nonmetals

To the right of the stair-step line Typically gasses with low melting points Very poor conductors of heat and electricity Brittle break rather than change shape

Nonmetals As you move right across the periodic table, nonmetals become more reactive As you move down a group (family), nonmetals become less reactive

Where are the most reactive nonmetals? Exit Ticket 1. 2. 3.

4. On the index card, please answer the following questions: Which group is the halogens? What is the most reactive nonmetal? What is the most reactive metal? List two metalloids.