Searching For an Organizing Principle

1. 6.1 Searching For an Organizing Principle • Searching For an Organizing Principle • How did chemists begin to organize the known elements?

2. 6.1 Searching For an Organizing Principle • Chemists used the properties of elements to sort them into groups.

3. 6.1 Searching For an Organizing Principle • Chlorine, bromine, and iodine have very similar chemical properties.

4. 6.1 Mendeleev’s Periodic Table • Mendeleev’s Periodic Table • How did Mendeleev organize his periodic table?

5. 6.1 Mendeleev’s Periodic Table • Mendeleev arranged the elements in his periodic table in order of increasing atomic mass. • The periodic table can be used to predict the properties of undiscovered elements.

6. 6.1 Mendeleev’s Periodic Table • An Early Version of Mendeleev’s Periodic Table

7. 6.1 The Periodic Law • The Periodic Law • How is the modern periodic table organized?

8. 6.1 The Periodic Law • In the modern periodic table, elements are arranged in order of increasing atomic number.

9. 6.1 The Periodic Law • The periodic law: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties. • The properties of the elements within a period change as you move across a period from left to right. • The pattern of properties within a period repeats as you move from one period to the next.

10. 6.1 Metals, Nonmetals, and Metalloids • Metals, Nonmetals, and Metalloids • What are three broad classes of elements?

11. 6.1 Metals, Nonmetals, and Metalloids • Three classes of elements are metals, nonmetals, and metalloids. • Across a period, the properties of elements become less metallic and more nonmetallic.

12. 6.1 Metals, Nonmetals, and Metalloids • Metals, Metalloids, and Nonmetals in the Periodic Table

13. 6.1 Metals, Nonmetals, and Metalloids • Metals, Metalloids, and Nonmetals in the Periodic Table

14. 6.1 Metals, Nonmetals, and Metalloids • Metals, Metalloids, and Nonmetals in the Periodic Table

15. 6.1 Metals, Nonmetals, and Metalloids • Metals, Metalloids, and Nonmetals in the Periodic Table

16. 6.1 Metals, Nonmetals, and Metalloids • Metals • Metals are good conductors of heat and electric current. • 80% of elements are metals. • Metals have a high luster, are ductile, and are malleable.

17. 6.1 Metals, Nonmetals, and Metalloids • Uses of Iron, Copper, and Aluminum

18. 6.1 Metals, Nonmetals, and Metalloids • Uses of Iron, Copper, and Aluminum

19. 6.1 Metals, Nonmetals, and Metalloids • Uses of Iron, Copper, and Aluminum

20. 6.1 Metals, Nonmetals, and Metalloids • Nonmetals • In general, nonmetals are poor conductors of heat and electric current. • Most nonmetals are gases at room temperature. • A few nonmetals are solids, such as sulfur and phosphorus. • One nonmetal, bromine, is a dark-red liquid.

21. 6.1 Metals, Nonmetals, and Metalloids • 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.

22. 6.1 Metals, Nonmetals, and Metalloids • 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.

23. 6.1 Section Quiz • 1. The modern periodic table has elements arranged in order of • colors. • melting and boiling points. • increasing atomic mass. • increasing atomic number.

24. 6.1 Section Quiz • 2. Mendeleev arranged the elements in his periodic table in order of increasing • atomic number. • number of protons. • number of electrons. • atomic mass

25. 6.1 Section Quiz • 3. Which one of the following is NOT a general property of metals? • ductility • malleability • having a high luster • poor conductor of heat and electricity

26. END OF SHOW