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.. How can you organize and classify elements? CHEMISTRY & YOU If you have ever played a card game, then you have probably organized your cards. Maybe you classified them by color or number.

3. 6.1 Organizing the Elements > 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Searching for an Organizing Principle How did chemists begin to organize the known elements? 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. Searching for an Organizing Principle –Chemists suspected that other elements existed. –In one decade (1765–1775), chemists discovered five new elements. There were only 13 elements identified by the year 1700. As chemists began to use scientific methods to search for elements, the rate of discovery increased #1 #2

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, published a classification system. In his system, the known elements were grouped into triads. A triad is a set of three elements with similar properties. –The elements shown here formed one triad. Chlorine, bromine, and iodine may look different, but they have very similar chemical properties. Early chemists used the properties of elements to sort them into groups. #3 #4

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? Mendeleev’s Periodic Table

7. 6.1 Organizing the Elements > 7 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. In 1869, a Russian chemist and teacher, Dmitri Mendeleev, published a table of the elements. Mendeleev’s Periodic Table He wrote the properties of each element on a separate note card. This approach allowed him to move the cards around until he found an organization that worked. #5

8. 6.1 Organizing the Elements > 8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Elements in a periodic table are arranged into groups based on a set of repeating properties. Mendeleev arranged the elements in his periodic table in order of increasing atomic mass. Mendeleev’s Periodic Table The organization he chose was a periodic table. #6

9. 6.1 Organizing the Elements > 9 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Mendeleev’s Periodic Table Mendeleev arranged elements with similar properties in the same row.

10. 6.1 Organizing the Elements > 10 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Mendeleev’s Periodic Table Mendleev predicted the existence and properties of undiscovered elements. #7

11. 6.1 Organizing the Elements > 11 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Mendeleev’s Periodic Table gallium and germanium, which were discovered in 1875 and 1886 to fill the spaces.

12. 6.1 Organizing the Elements > 12 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. In a periodic table based on atomic mass, iodine should come before tellurium since iodine has a smaller atomic mass than tellurium does. However, based on its chemical properties, iodine belongs in a group with bromine and chlorine. Today’s Periodic Table Problems with Mendeleev’s Periodic Table using Atomic Mass to order elements

13. 6.1 Organizing the Elements > 13 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Mendeleev placed tellurium before iodine in his periodic table. He assumed that the atomic masses for iodine and tellurium were incorrect, but they were not. A similar problem occurred with other pairs of elements. The problem wasn’t with the atomic masses but with using atomic mass to organize the periodic table. Today’s Periodic Table

14. 6.1 Organizing the Elements > 14 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Mendeleev developed his table before scientists knew about the structure of atoms. He didn’t know that the atoms of each element contain a unique number of protons. Recall that the number of protons is the atomic number. Today’s Periodic Table

15. 6.1 Organizing the Elements > 15 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. #8

16. 6.1 Organizing the Elements > 16 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Today’s Periodic Table The vertical columns are called groups and the horizontal rows are called periods #9

17. 6.1 Organizing the Elements > 17 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. #10

18. 6.1 Organizing the Elements > 18 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. 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. Today’s Periodic Table This pattern gives rise to the periodic law: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties. #11

19. 6.1 Organizing the Elements > 19 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 (or group) 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. #12

20. 6.1 Organizing the Elements > 20 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Metals, Nonmetals, and Metalloids What are the three broad classes of elements? Metals, Nonmetals, and Metalloids

21. 6.1 Organizing the Elements > 21 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 Three classes of elements are metals, nonmetals, and metalloids. #13

22. 6.1 Organizing the Elements > 22 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Scientists in the United States primarily use the labels shown in red. Scientists in Europe use the labels shown in blue The International Union of Pure and Applied Chemistry (IUPAC) uses 1-18. Metals, Nonmetals, and Metalloids

23. 6.1 Organizing the Elements > 23 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Three classes of elements are metals, nonmetals, and metalloids. Metals, Nonmetals, and Metalloids Across a period, the properties of elements become less metallic and more nonmetallic. #14

24. 6.1 Organizing the Elements > 24 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Most periodic tables are laid out like the one on the previous slide. Notice that some elements from Periods 6 and 7 are placed beneath the table, making the table more compact and reflecting a structure you will study in Lesson 6.2. Metals, Nonmetals, and Metalloids

25. 6.1 Organizing the Elements > 25 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Each column, or group, in this table has three labels. Scientists in the United States primarily use the labels shown in red. Scientists in Europe use the labels shown in blue. Metals, Nonmetals, and Metalloids

26. 6.1 Organizing the Elements > 26 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. The International Union of Pure and Applied Chemistry (IUPAC) is an organization that sets standards for chemistry. Metals, Nonmetals, and Metalloids In 1985, IUPAC proposed a new system for labeling groups in the periodic table. They numbered the groups from left to right 1 through 18 (the black labels).

27. 6.1 Organizing the Elements > 27 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Dividing the elements into groups is not the only way to classify them based on their properties. Metals, Nonmetals, and Metalloids The elements can be grouped into three broad classes based on their general properties.

28. 6.1 Organizing the Elements > 28 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

29. 6.1 Organizing the Elements > 29 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. 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. Metals are generally good conductors of heat and electric current. #15

30. 6.1 Organizing the Elements > 30 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 #15

31. 6.1 Organizing the Elements > 31 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. #15

32. 6.1 Organizing the Elements > 32 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Blue is used to identify the nonmetals. Nonmetals Metals, Nonmetals, and Metalloids

33. 6.1 Organizing the Elements > 33 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. There is a greater variation in physical properties among nonmetals than among metals. Nonmetals Metals, Nonmetals, and Metalloids Most nonmetals are gases at room temperature, including the main components of air—nitrogen and oxygen. A few are solids, such as sulfur and phosphorus. One nonmetal, bromine, is a dark-red liquid. #16 #17

34. 6.1 Organizing the Elements > 34 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.

35. 6.1 Organizing the Elements > 35 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. #18

36. 6.1 Organizing the Elements > 36 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.

37. 6.1 Organizing the Elements > 37 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Under some conditions, metalloids may behave like metals. Under other conditions, they may behave like nonmetals. Metals, Nonmetals, and Metalloids Metalloids The behavior can often be controlled by changing the conditions. #19

38. 6.1 Organizing the Elements > 38 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.

39. 6.1 Organizing the Elements > 39 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. All of the known elements are listed in the periodic table. What are different ways you could use the periodic table to classify elements? CHEMISTRY & YOU

40. 6.1 Organizing the Elements > 40 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. All of the known elements are listed in the periodic table. What are different ways you could use the periodic table to classify elements? You can use the periodic table to classify elements by their atomic weight, by their chemical properties, by their physical properties, or by their electron configuration. CHEMISTRY & YOU

41. 6.1 Organizing the Elements > 41 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Is there more variety of properties among metals or among nonmetals?

42. 6.1 Organizing the Elements > 42 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Is there more variety of properties among metals or among nonmetals? The properties of metals are more constant. There is more variety among the properties of nonmetals.

43. 6.1 Organizing the Elements > 43 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

44. 6.1 Organizing the Elements > 44 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Glossary Terms periodic law: when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties metal: one of a class of elements that are good conductors of heat and electric current; metals tend to be ductile, malleable, and shiny

45. 6.1 Organizing the Elements > 45 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Glossary Terms nonmetal: an element that tends to be a poor conductor of heat and electric current; nonmetals generally have properties opposite to those of metals metalloid: an element that tends to have properties that are similar to those of metals and nonmetals

46. 6.1 Organizing the Elements > 46 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. Periodic tables may contain each element’s name, symbol, atomic number, and atomic mass. BIG IDEA Electrons and the Structure of Atoms

47. 6.1 Organizing the Elements > 47 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.. END OF 6.1