1. Chapter 6

2. 6.1  In a self-service store, the products are grouped according to similar characteristics. With a logical classification system, finding and comparing products is easy. You will learn how elements are arranged in the periodic table and what that arrangement reveals about the elements.

3.  Searching For an Organizing Principle ◦ How did chemists begin to organize the known elements? 6.1

4.  Chemists used the properties of elements to sort them into groups. 6.1

5.  Chlorine, bromine, and iodine have very similar chemical properties. 6.1

6.  Mendeleev’s Periodic Table ◦ How did Mendeleev organize his periodic table? 6.1

7.  Mendeleev organized elements into a periodic table.  This table arranged elements into groups based on a set of repeating properties and according to increasing atomic mass.  The periodic table can be used to predict the properties of undiscovered elements. 6.1

8.  An Early Version of Mendeleev’s Periodic Table 6.1

9.  The Periodic Law ◦ How is the modern periodic table organized? 6.1

10.  In the modern periodic table, elements are arranged in order of increasing atomic number. 6.1

11.  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. 6.1

12.  Metals, Nonmetals, and Metalloids ◦ What are three broad classes of elements? 6.1

13. ◦ Three classes of elements are metals, nonmetals, and metalloids. 6.1

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

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

16. ◦ Metals  Metals are good conductors of heat and electric current.  80% of elements are metals.  All metals are solids at room temperature except mercury, which is a liquid.  Metals have a high luster, are ductile, and are malleable. 6.1

17.  Uses of Iron, Copper, and Aluminum 6.1

18.  Uses of Iron, Copper, and Aluminum 6.1

19.  Uses of Iron, Copper, and Aluminum 6.1

20.  Metals, Metalloids, and Nonmetals in the Periodic Table 6.1

21. ◦ 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. 6.1

23.  Metals, Metalloids, and Nonmetals in the Periodic Table 6.1

24. ◦ 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.  Metalloids are also known as semi-metals. 6.1

25.  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

26. ◦ Across a period, the properties of elements become less metallic and more nonmetallic. ◦ Down a group, the properties of elements become more metallic and less nonmetallic.

27. 6.2  A coin may contain much information in a small space—its value, the year it was minted, and its country of origin. Each square in a periodic table also contains information. You will learn what types of information are usually listed in a periodic table.

28. 6.2  Squares in the Periodic Table ◦ What type of information can be displayed in a periodic table?

29.  The periodic table displays the symbols and names of the elements, along with information about the structure of their atoms. 6.2

30. http://www.privatehand.com/flash/elements.html

31.  Some element families have names:  The Group 1 elements are called alkali metals.  The Group 2 elements are called alkaline earth metals.  The nonmetals of Group 17 are called halogens.  The nonmetal gases of group 18 are called noble gases. 6.2

33.  Electron Configurations in Groups ◦ How can elements be classified based on their electron configurations? 6.2

34.  Elements can be sorted into groups based on their electron configurations.  Elements in the same family have the same outer electron configuration = valence electrons. 6.2

35. ◦ The Noble Gases  The noble gases are the elements in Group 18 of the periodic table.  All noble gases except helium have 8 valence electrons. 6.2

36.  The blimp contains helium, one of the noble gases. 6.2

37. ◦ The alkali metals.  In atoms of the Group 1 elements below, there is only one electron in the highest occupied energy level; one valence electron. 6.2

38. ◦ The carbon family  In atoms of the Group 14 elements below, there are four valence electrons. 6.2

43.  Transition Elements  There are two types of transition elements—transition metals and inner transition metals. They are classified based on their electron configurations. 6.2

44.  In atoms of a transition metal, the d sublevel is filling with electrons.  In atoms of an inner transition metal, the f sublevel is filling with electrons. 6.2

45. ◦ Blocks of Elements 6.2

46. ..\..\..\..\Videos\RealPlayer Downloads\Teachers' Domain The Elements Forged in Stars.mov..\..\..\..\Videos\RealPlayer Downloads\Teachers' Domain The Elements Forged in Stars.mov

47.  In the Earth’s Crust: ◦ Oxygen ◦ Silicon ◦ Aluminum ◦ Iron ◦ Calcium ◦ Sodium ◦ Potassium ◦ Magnesium ◦ Titanium ◦ Hydrogen

48.  Dissolved in the Oceans: ◦ Chlorine ◦ Sodium ◦ Magnesium ◦ Sulfur ◦ Calcium ◦ Potassium ◦ Bromine ◦ Carbon ◦ Strontium ◦ Boron

49.  In the Atmosphere: ◦ Nitrogen ◦ Oxygen ◦ Argon ◦ Neon ◦ Helium ◦ Krypton ◦ Hydrogen ◦ Xenon ◦ Radon

50.  In the Sun: ◦ Hydrogen ◦ Helium ◦ Oxygen ◦ Carbon ◦ Nitrogen ◦ Silicon ◦ Magnesium ◦ Neon ◦ Iron ◦ Sulfur

51.  In your body: ◦ Oxygen ◦ Carbon ◦ Hydrogen ◦ Nitrogen ◦ Calcium ◦ Phosphorus ◦ Sulfur ◦ Potassium ◦ Sodium ◦ Chlorine

52.  Soft, silver-grey metals.  Low melting and boiling points.  Electron configuration ends in s 1.  Most reactive: not found uncombined in nature.  Obtained in the pure form by electrolysis of their fused salts.  Potassium Video - The Periodic Table of Videos - University of Nottingham Potassium Video - The Periodic Table of Videos - University of Nottingham

53.  Relatively soft, but harder than alkali metals.  Although not as reactive as alkali metals, still very reactive and not found in nature in the elemental state.  Electron configuration ends in s 2.  Obtained in the pure form through electrolysis of their fused salts.  Densities, melting and boiling points are higher than respective alkali metals.  Radium Video - The Periodic Table of Videos - University of Nottingham Radium Video - The Periodic Table of Videos - University of Nottingham

54.  Most are ductile, malleable and good conductors of heat and electricity.  Compounds of transition metals tend to have color.  d sublevel is filling.  Obtained from mineral deposits in the earth’s crust.  Precious metals are used for currency among other things.  Darmstadtium Video - The Periodic Table of Videos - University of Nottingham Darmstadtium Video - The Periodic Table of Videos - University of Nottingham

55.  Nonmetals.  Very reactive; not found in nature uncombined.  Electron configuration ends in s 2 p 5.  Obtained from the electrolysis of their fused salts.  Commercial applications include antibecterial properties.  Chlorine Video - The Periodic Table of Videos - University of Nottingham Chlorine Video - The Periodic Table of Videos - University of Nottingham

56.  Non-reactive (inert) gases.  Electron configuration ends in s 2 p 6 (except He is just s 2 ).  Rarely form compounds; can combine with fluorine.  Commercial applications include colored signs lit up as discharge tubes.  Incandescent light bulbs are filled with argon.  Radon Video - The Periodic Table of Videos - University of Nottingham Radon Video - The Periodic Table of Videos - University of Nottingham

57.  Sodium chloride (table salt) produced the geometric pattern in the photograph. Such a pattern can be used to calculate the position of nuclei in a solid. You will learn how properties such as atomic size are related to the location of elements in the periodic table. 6.3

58.  Trends in Atomic Size ◦ What are the trends among the elements for atomic size? 6.3

59.  The atomic radius is one half of the distance between the nuclei of two atoms of the same element when the atoms are joined. 6.3

60. ◦ Group and Periodic Trends in Atomic Size  In general, atomic size increases from top to bottom within a group and decreases from left to right across a period.  Down a group, atomic size increases due to additional energy levels.  Across a period atomic size decreases due to increasing nuclear charge. 6.3

63.  Ions ◦ How do ions form? 6.3

64.  Positive ions form when an atom loses electron(s). 6.3

65.  Negative ions form when an atom gains electron(s). 6.3

66.  Some compounds are composed of particles called ions.  An ion is an atom or group of atoms that has a positive or negative charge.  A cation is an ion with a positive charge.  An anion is an ion with a negative charge. 6.3

67.  Trends in Ionization Energy ◦ What are the trends among the elements for first ionization energy, ionic size, and electronegativity? 6.3

68.  The energy required to remove an electron from an atom is called ionization energy.  The energy required to remove the first electron from an atom is called the first ionization energy.  The energy required to remove a second electron is called the second ionization energy. 6.3

69. ◦ Group and Periodic Trends in Ionization Energy  First ionization energy tends to decrease from top to bottom within a group and increase from left to right across a period.  Down a group increasing levels of electrons shield the effect of the nucleus therefore reducing energy needed to remove an outer electron.  Across a period there in no increase in energy levels, and increasing nuclear charge makes it more difficult to remove an outer electron. 6.3

72.  Trends in Ionic Size  During reactions between metals and nonmetals, metal atoms tend to lose electrons, and nonmetal atoms tend to gain electrons. The transfer has a predictable effect on the size of the ions that form. 6.3

73.  Cations are always smaller than the atoms from which they form.  Anions are always larger than the atoms from which they form. 6.3

74.  Relative Sizes of Some Atoms and Ions 6.3

75.  Trends in Ionic Size 6.3 Size generallyincreases

76.  Trends in Electronegativity  Electronegativity is the ability of an atom to attract electrons to itself when it is in involved in a bond. 6.3

77.  Trends in Electronegativity  In general, electronegativity values decrease from top to bottom within a group, and increase from left to right across a period.  Electronegativity decreases down a group because of increasing atomic size and the shielding effect of inner level electrons.  Electronegativity increases across a period because of decreasing atomic size and increasing nuclear charge.

78.  Summary of Trends ◦ What is the underlying cause of periodic trends? 6.3

79.  Periodic trends can be explained by variations in atomic structure. ◦ Nuclear charge ◦ Shielding effect 6.3