How did chemists begin to organize the known elements? 6.1 How did chemists begin to organize the known elements? Chemists used the properties of elements to sort them into groups Chlorine, bromine, and iodine have very similar chemical properties. (Dobereiner, 1829) Chlorine, bromine, and iodine have very similar chemical properties. The numbers shown are the average atomic masses for these elements.

Metals, Nonmetals, and Metalloids 6.1 Metals, Nonmetals, and Metalloids Metals, Metalloids, and Nonmetals in the Periodic Table One way to classify elements in the periodic table is as metals, nonmetals, and metalloids. Inferring What is the purpose for the black stair-step line?

6.1 Metals One way to classify elements in the periodic table is as metals, nonmetals, and metalloids. Inferring What is the purpose for the black stair-step line?

Physical Properties of Metals Have a high luster ( shiny) Solid at room temperature Are good conductors(of heat and electric current) Are ductile (the ability to be pulled into a thin strand like wire) Are malleable (the ability to be pressed or pounded in to a thin sheet)

6.1 Metals Usage Uses of Iron, Copper, and Aluminum The metals iron, copper, and aluminum have many important uses. How each metal is used is determined by its properties.

6.1 Metals If a small amount of boron is mixed with silicon, the mixture is a good conductor of electric current. Silicon can be cut into wafers, and used to make computer chips.

6.1 Nonmetals . One way to classify elements in the periodic table is as metals, nonmetals, and metalloids. Inferring What is the purpose for the black stair-step line?

Physical Properties of Nonmetals dull luster (not shiny) gas at room temperature(some are not a gas at room temperature) not ductile (the ability to be pulled into a thin strand like wire) Insulator (dose not conduct electricity) Brittle (break and shatters easily)

6.1 Metalloids One way to classify elements in the periodic table is as metals, nonmetals, and metalloids. Inferring What is the purpose for the black stair-step line?

Metalloids A metalloid generally has properties that are similar to those of metals and nonmetals. The behavior of a metalloid can be controlled by changing conditions. The most important use of metalloids is as of “semiconductors”, substances who can change the amount of electricity that they conduct -- based on heat, light, etc. . . -- very useful in computer chips