1. 6.1 Organizing the Elements > 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Chapter 6 The Periodic Table 6.1 Organizing the Elements 6.2 Classifying the Elements 6.3 Periodic Trends

2. 6.1 Organizing the Elements > 2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Do Now: CHEMISTRY & YOU Sort and organize the deck of cards at your table. Be prepared to discuss the classification system you used.

3. 6.1 Organizing the Elements > 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. What elements are you familiar with? Searching for an Organizing Principle

4. 6.1 Organizing the Elements > 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. A few elements, including copper, silver, and gold, have been known for thousands of years. There were only 13 elements identified by the year 1700. Searching for an Organizing Principle –Chemists suspected that other elements existed. –As chemists began to use scientific methods to search for elements, the rate of discovery increased. –In one decade (1765–1775), chemists discovered five new elements.

5. 6.1 Organizing the Elements > 5 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Searching for an Organizing Principle In 1829, a German chemist, J. W. Dobereiner, classified elements into triads. A triad is a set of three elements with similar properties. Early chemists used the properties of elements to sort them into groups. –The elements shown are chlorine, bromine, and iodine. They look different, but have similar chemical properties.

6. 6.1 Organizing the Elements > 6 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Mendeleev’s Periodic Table How did Mendeleev organize his periodic table? https://www.youtube.com/watch?v=0RR VV4Diomg Mendeleev’s Periodic Table

7. 6.1 Organizing the Elements > 7 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Mendeleev’s Periodic Table Mendeleev arranged elements with similar properties in the same row.

8. 6.1 Organizing the Elements > 8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Today’s Periodic Table In the modern periodic table, elements are arranged in order of increasing atomic number.

9. 6.1 Organizing the Elements > 9 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Today’s Periodic Table There are seven rows, or periods, in the table. Each period corresponds to a principal energy level. There are more elements in higher- numbered periods because there are more orbitals in higher energy levels.

10. 6.1 Organizing the Elements > 10 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Today’s Periodic Table Elements that have similar chemical and physical properties end up in the same column in the periodic table. When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties.

11. 6.1 Organizing the Elements > 11 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Are elements with similar properties found in the rows (periods) or columns (groups) of the modern periodic table?

12. 6.1 Organizing the Elements > 12 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Are elements with similar properties found in the rows (periods) or columns (groups) of the modern periodic table? Elements with similar properties are found in the columns, or groups, of the modern periodic table.

13. 6.1 Organizing the Elements > 13 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Periodic tables are sometimes color-coded to classify types of elements. Metals, Nonmetals, and Metalloids

14. 6.1 Organizing the Elements > 14 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Three classes of elements are metals, nonmetals, and metalloids. Across a period, the properties of elements become less metallic and more nonmetallic. Metals, Nonmetals, and Metalloids

15. 6.1 Organizing the Elements > 15 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. The number of yellow squares in the table shows that most elements are metals— about 80%. Metals Metals, Nonmetals, and Metalloids

16. 6.1 Organizing the Elements > 16 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Metals are generally good conductors of heat and electric current. Metals, Nonmetals, and Metalloids Metals Copper is second only to silver as a conductor of electric current. The copper used in electrical cables must be 99.99 percent pure.

17. 6.1 Organizing the Elements > 17 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. A freshly cleaned or cut surface of a metal will have a high luster, or sheen. The sheen is caused by the metal’s ability to reflect light. All metals are solids at room temperature, except for mercury (Hg). Metals, Nonmetals, and Metalloids Metals

18. 6.1 Organizing the Elements > 18 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Most metals are malleable, meaning that they can be hammered into thin sheets without breaking. Metals, Nonmetals, and Metalloids Metals Many metals are ductile, meaning that they can be drawn into wires.

19. 6.1 Organizing the Elements > 19 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Blue is used to identify the nonmetals. Nonmetals Metals, Nonmetals, and Metalloids

20. 6.1 Organizing the Elements > 20 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. The variation among nonmetals makes it difficult to describe one set of general properties that will apply to all nonmetals. Nonmetals Metals, Nonmetals, and Metalloids A diamond, which is composed of carbon, is very hard. Some match heads are coated with phosphorus, a brittle solid.

21. 6.1 Organizing the Elements > 21 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Nonmetals tend to have properties that are opposite to those of metals. Nonmetals Metals, Nonmetals, and Metalloids In general, nonmetals are poor conductors of heat and electric current. Carbon, in the form of graphite, is an exception to this rule. Solid nonmetals tend to be brittle, meaning that they will shatter if hit with a hammer.

22. 6.1 Organizing the Elements > 22 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. There is a heavy stair-step line that separates the metals from the nonmetals. Metalloids Metals, Nonmetals, and Metalloids Most of the elements that border this line are shaded green. These elements are metalloids.

23. 6.1 Organizing the Elements > 23 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. A metalloid generally has properties that are similar to those of metals and nonmetals. Metals, Nonmetals, and Metalloids Metalloids

24. 6.1 Organizing the Elements > 24 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Like most nonmetals, pure silicon is a poor conductor of electric current. However, if a small amount of boron is mixed with the silicon, the mixture is a good conductor of electric current. Metals, Nonmetals, and Metalloids Metalloids Silicon is also present as the compound silicon dioxide in glass items. Silicon can be cut into wafers and used to make computer chips.

25. 6.1 Organizing the Elements > 25 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Early chemists used the properties of elements to sort them into groups. Mendeleev arranged the elements in his periodic table in order of increasing atomic mass. In the modern periodic table, elements are arranged in order of increasing atomic number. Three classes of elements are metals, nonmetals, and metalloids. Key Concepts