Chapter 1 Section 3: Elements - PDF

SECTION 3 Main Ideas The periodic table organizes Elements elements by their chemical Key Terms properties. group period nonmetal family...

SECTION 3 Main Ideas The periodic table organizes Elements elements by their chemical Key Terms properties. group period nonmetal family metal metalloid Some elements are metals. Some elements are nonmetals As you have read, elements are pure substances that cannot be decomposed by chemical changes. The elements serve as the building blocks of matter. Each or metalloids. element has characteristic properties. The elements are organized into groups based on similar chemical properties. This organization of elements is the periodic table, which is shown in Figure 3.2 on the next page. MAIN IDEA The periodic table organizes elements by their chemical properties. Each small square of the periodic table shows the symbol for an element and its atomic number. For example, the first square, at the upper left, represents element 1, hydrogen, which has the symbol H. As you look through the table, you will see many familiar elements, including iron, sodium, neon, silver, copper, aluminum, sulfur, and lead. You can often relate an element’s symbol to its English name. Some symbols come from the element’s older name, which was often in Latin. Still others come from German. For example, the symbol W for tungsten comes from its German name, wolfram. Figure 3.1 lists some elements and their older names. FIGURE 3.1 ELEMENTS WITH SYMBOLS BASED ON OLDER NAMES Modern name Symbol Older name antimony Sb stibium copper Cu cuprum gold Au aurum iron Fe ferrum lead Pb plumbum mercury Hg hydrargyrum potassium K kalium silver Ag argentum sodium Na natrium tin Sn stannum tungsten W wolfram 20 Chapter 1 FIGURE 3.2 GO ONLINE The Periodic Table The names of the elements can be found in Chemistry the larger periodic table inside the back cover of your book. HMHScience.com The Organization of the Periodic Table Group 18 1 2 H He Group 1 Group 2 Metals Group 13 Group 14 Group 15 Group 16 Group 17 3 4 5 6 7 8 9 10 Metalloids Li Be B C N O F Ne 11 12 Nonmetals 13 14 15 16 17 18 Na Mg Group 3 Group 4 Group 5 Group 6 Group 7 Group 8 Group 9 Group 10 Group 11 Group 12 Al Si P S Cl Ar 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 87 88 89 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr The vertical columns of the periodic table are called groups, or families. Notice that they are numbered from 1 to 18 from left to right. Each group contains elements with similar chemical properties. For example, the elements in Group 2 are beryllium, magnesium, calcium, strontium, barium, and radium. All of these elements are reactive metals with similar abilities to bond to other kinds of atoms. The two major categories of elements are metals and nonmetals. Metalloids have properties intermediate between those of metals and nonmetals. The horizontal rows of elements in the periodic table are called periods. Physical and chemical properties change somewhat regularly across a period. Elements that are close to each other in the same period tend to be more similar than elements that are farther apart. For example, in Period 2, the elements lithium and beryllium, in Groups 1 and 2, respec- tively, are somewhat similar in properties. However, their properties are very different from the properties of fluorine. The two sets of elements placed below the periodic table make up what are called the lanthanide series and the actinide series. These metallic elements fit into the table just after elements 57 and 89. They are placed below the table to keep the table from being too wide. There is a section in the back of this book called the Elements Handbook (Appendix A), which covers some elements in greater detail. You will use information from the handbook to complete the questions in the Using the Handbook sections in the chapter reviews. Matter and Change 21  MAIN IDEA Superconductors Some elements are metals. The periodic table is broadly divided into two main sections: metals and Any metal becomes a better conductor of electrical energy as nonmetals. As you can see in Figure 3.2 on the previous page, the metals its temperature decreases. In 1911, are at the left and in the center of the table. The nonmetals are toward the scientists discovered that when right. Some elements, such as boron and silicon, show characteristics of mercury is cooled to about -269°C, both metals and nonmetals. it loses all resistance and becomes Some of the properties of metals may be familiar to you. For example, a superconductor. Scientists have you can recognize metals by their shininess, or metallic luster. Perhaps long tried to find a material that the most important characteristic property of metals is the ease with would superconduct at temperatures which they conduct electricity and transfer energy. Thus, a metal is an above -196°C, the boiling point of element that is a good electrical conductor and a good heat conductor. liquid nitrogen. In 2014, scientists At room temperature, most metals are solids. Most metals also have held a ceramic in a superconducting state at room temperature for a the property of malleability; that is, they can be hammered or rolled into few picoseconds. High-temperature thin sheets. Metals also tend to be ductile, which means that they can be superconductors (HTS) could reduce drawn into a fine wire. Metals behave this way because they have high the need for special cooling systems to tensile strength, the ability to resist breaking when pulled. maintain superconductivity. Potential Although all metals conduct electricity well, metals also have very uses include smaller and less costly diverse properties. Mercury is a liquid at room temperature, whereas superconducting magnets, motors, tungsten has the highest melting point of any element. The metals in generators, MRI machines, and Group 1 are so soft that they can be cut with a knife, yet others, such as refrigerators. Wider use of HTS cables chromium, are very hard. Some metals, such as manganese and bismuth, and wires in power transmission are very brittle, yet others, such as iron and copper, are very malleable systems might result in power and ductile. Most metals have a silvery or grayish white luster. Two systems built closer to consumers. exceptions are gold and copper, which are yellow and reddish brown, HTS use in computer chips and digital respectively. Figure 3.3 shows three examples of metals: gold, copper, routers could transmit data faster. and aluminum. FIGURE 3.3 Characteristic Properties of Metals (bc) ©Ron Elmy/First Light/Alamy (a) Gold has a low reactivity, which (b) Copper is used in wiring because it (c) Aluminum is malleable. It can be rolled is why it may be found in nature in is ductile and conducts electrical energy. into foil that is used for wrapping food. relatively pure form. 22 Chapter 1  Copper, shown in Figure 3.3b, has a characteristic reddish color and a metallic luster. It is found naturally in minerals such as chalcopyrite and malachite. Pure copper melts at 1083°C and boils at 2567°C. It can be readily drawn into fine wire, pressed into thin sheets, and formed into tubing. Copper conducts electricity with little loss of energy. Copper remains unchanged in pure, dry air at room temperature. When heated, it CHECK FOR UNDERSTANDING reacts with oxygen in air. It also reacts with sulfur and the elements in Mercury is a metal that is liquid at Group 17 of the periodic table. The green coating on a piece of weathered room temperature. Using the Elements copper comes from the reaction of copper with oxygen, carbon dioxide, and Handbook (Appendix A) as a reference, sulfur compounds. Copper is also an essential mineral in the human diet. are there any nonmetals that are liquids at room temperature? MAIN IDEA Some elements are nonmetals or metalloids. Many nonmetals are gases at room temperature. These include nitrogen, oxygen, fluorine, and chlorine. One nonmetal, bromine, is a liquid. The solid nonmetals include carbon, phosphorus, selenium, sulfur, and iodine. These solids tend to be brittle rather than malleable and ductile. Some nonmetals are illustrated in Figure 3.4. Low conductivity can be used to define nonmetals. A nonmetal is an element that is a poor conductor of heat and electricity. If you look at the periodic table, you will see that there are fewer nonmetals than metals. Phosphorus, shown in Figure 3.4c, is one of five solid nonmetals. Pure phosphorus is known in two common forms. Red phosphorus is a dark red powder that melts at 597°C. White phosphorus is a waxy solid that melts at 44°C. Because it ignites in air at room temperature, white phosphorus is stored under water. Phosphorus is too reactive to exist in pure form in nature. It is present in huge quantities in phosphate rock, where it is combined with oxygen and calcium. All living things contain phosphorus. FIGURE 3.4 Nonmetallic Elements (a) Carbon (b) Sulfur (c) Phosphorus (d) Iodine Matter and Change 23  FIGURE 3.5 Noble Gases Some noble gases are used to make lighted signs of various colors. The elements in Group 18 of the periodic table are the noble gases. These elements are generally unreactive, although some can be made to form compounds, such as xenon hexafluoroplatinate. Low reactivity makes the noble gases very different from the other families of elements. Group 18 elements are gases at room temperature. Neon, argon, krypton, and xenon are all used to make lighted signs, like the one in Figure 3.5. As you look from left to right on the periodic table, you can see that the metalloids are found between the metals and the nonmetals. A metalloid is an element that has some characteristics of metals and some characteristics of nonmetals. All metalloids are solids at room temperature. They tend to be less malleable than metals but not as brittle as nonmet- als. Some metalloids, such as antimony, have a somewhat metallic luster. Metalloids tend to be semiconductors of electricity. That is, their ability to conduct electricity is intermediate between that of metals and that of nonmetals. Metalloids are used in the solid-state circuitry found in desktop computers, digital watches, televisions, and radios. SECTION 3 FORMATIVE ASSESSMENT Reviewing Main Ideas 4. Describe the main differences between metals, nonmetals, and metalloids. 1. Use the periodic table to write the names for the ©C. Bradley Simmons/Bruce Coleman, Inc following elements: O, S, Cu, Ag. Critical Thinking 2. Use the periodic table to write the symbols for 5. INFERRING CONCLUSIONS If you find an the following elements: iron, nitrogen, calcium, element in nature in its pure elemental state, mercury. what can you infer about the element’s chemical 3. Which elements are most likely to undergo the reactivity? How can you tell whether that same kinds of reactions, those in a group or element is a metal or a nonmetal? those in a period? 24 Chapter 1