Properties of Metals, Nonmetals, and Metalloids

The importance of families of elements is that elements in the same family tend to have similar chemical and physical properties. Having similar chemical properties means that they form compounds with similar formulas. For example, the oxides of the alkaU metals 

With the exception of the noble gases, which occupy the last column of the periodic table and are exceptionally nonreactive, the most chemically reactive elements are located both at the far left side and the far right side of the table. The least reactive elements tend to be located in the central part of the table. 

A triad is a group of three elements with very similar chemical and physical properties. The properties of the element in the middle of a triad are often the average of the properties of the elements on either side of it. Triads usually are found in the same column. Sometimes, however, triads are found in the same row, as is the case with iron, cobalt, and nickel. 

At the time Mendeleev developed the periodic table, a lot fewer elements were known. 

He often based his organization on what were called triads of elements—groups of three elements in the same vertical column with extremely similar properties. Examples of triads include vanadium, niobium, and tantalum in group VA sulfur, selenium, and tellurium in group VIB and chlorine, bromine, and iodine in group VllB. 

---

Know the properties of metals, nonmetals, and metalloids and which elements on the periodic table belong to each group. 

Most properties of metals, nonmetals, and metalloids are determined by their valence electron configurations. The number of valence electrons that a metal has varies with its position in the periodic table. Valence electrons in metal atoms tend to be loosely held. Nonmetals have four or more tightly held electrons, and metalloids have three to seven valence electrons. 

The more an element exhibits the physical and chemical properties of metals, the greater its metallic character. As indicated in Figure 7.12, metallic character generally increases as we proceed down a group of the periodic table and decreases as we proceed right across a period. Let s now examine the close relationships that exist between electron configurations and the properties of metals, nonmetals, and metalloids. 

Some Physical and Chemical Properties of Metals, Nonmetals, and Metalloids... 

Describe general properties of metals, nonmetals, and metalloids. 

Figure 9.1 A general comparison of metals and nonmetals. A, The positions of metals, nonmetals, and metalloids within the periodic table. B, The relative magnitudes of some key atomic properties vary from left to right within a period and correlate with whether an element is metallic or nonmetallic.

The elements can be divided into categories metals, nonmetals, and metalloids. Examples of each appear in Figure U. Except for hydrogen, all the elements in the left and central regions of the periodic table are metals. Metals display several characteristic properties. For example, they are good conductors of heat and electricity and usually appear shiny. Metals are malleable, meaning that they can be hammered into thin sheets, and ductile, meaning that they can be drawn into wires. Except for mercury, which is a liquid, all metals are solids at room temperature. 

Ion formation is only one pattern of chemical behavior. Many other chemical trends can be traced ultimately to valence electron configurations, but we need the description of chemical bonding that appears in Chapters 9 and 10 to explain such periodic properties. Nevertheless, we can relate important patterns in chemical behavior to the ability of some elements to form ions. One example is the subdivision of the periodic table into metals, nonmetals, and metalloids, first introduced in Chapter 1. 

You can use comparing and contrasting to help you classify objects or properties, differentiate between similar concepts, and speculate about new relationships. For example, as you read Chapters 1 and 2 you might begin to make a table in which you compare and contrast metals, nonmetals, and metalloids. As you continue to learn about these substances in the chapter on the Periodic Table, you can add to your table, giving you a better understanding of the similarities and differences among elements. 

Classifying the elements There are three main classifications for the elements—metals, nonmetals, and metalloids. Metals are elements that are generally shiny when smooth and clean, solid at room temperature, and good conductors of heat and electricity. Most metals also are malleable and ductile, meaning that they can be pounded into thin sheets and drawn into wires, respectively. Figure 6-6 shows several applications that make use of the physical properties of metals. 

The elements can be divided into three categories—metals, nonmetals, and metalloids. A metal is a good conductor of heat and electricity while a nonmetal is usually a poor conductor of heat and electricity. A metalloid has properties that are intermediate between those of metals and nonmetals. Figure 2.8 shows that the majority of known elements are metals only seventeen elements are nonmetals, and eight elements are metalloids. From left to right across any period, the physical and chemical properties of the elements change gradually from metallic to nonmetallic. 

Ss was menrioncd in Section 2.2, the periodic table is a listing of all die known elements. There is so much more to this table, however. Most notably, the elements arc organized in the table based on their physical and chemical properties. One of the most apparent examples is how the elements are grouped as metals, nonmetals, and metalloids. 

The elements can be broadly grouped as metals, nonmetals, and metalloids ( FIGURE 7.12). (Section 2.5) Some of the distinguishing properties of metals and nonmetals are summarized in T TABLE 7.3. 

Section 7.6 The elements can be categorized as metals, nonmetals, and metalloids. Most elements are metals titey occupy the left side and the middle of the periodic table. Nonmetals appear in the upper-right section of the table. Metalloids occupy a narrow band between the metals and nonmetals. The tendency of an element to exhibit the properties of metals, called the metallic character, increases as we proceed down a column and decreases as we proceed from left to right across a row. 

Correlations between electronic configurations for the elements and the periodic table arrangement of elements make it possible to determine a number of details of electronic structure for an element simply on the basis of the location of the element in the periodic table. Special attention is paid to the last or distinguishing electron in an element. Elements are classified according to the type of subshell (s, p, d, f) occupied by this electron. The elements are also classified on the basis of other properties as metals, nonmetals, or metalloids. 

Compare the physical properties of metals, nonmetals, metalloids, and noble gases, and describe where in the periodic table each of these kinds of elements is located. 

Simply stated, inorganic chemistry deals with the 117 elements in the periodic table other than carbon. The elements in the periodic table are broadly grouped into three classifications metals, nonmetals, and metalloids (or semimetals). Inorganic chemists describe the physical and chemical properties of the elements themselves, as well as all of the chemical compounds the elements can form, both in nature and in the laboratory. 

There are three classifications of elements metals, nonmetals, and metalloids. Metals are shown on the left side of the periodic table, nonmetals on the right, and metalloids between the two. Metalloids are elements that have properties intermediate between those of metals and nonmetals. 

The properties of the main-group elements show great diversity. Metals, nonmetals, and metalloids are all found among the main-group elements. 

The other elements, the ones to the right of the line and metalloids and also including hydrogen are classified as the nonmetals. The nonmetals have properties that are opposite of the metals. Many are not solid, they have a dull luster, are nonconductors, and are neither malleable nor ductile. The nonmetals tend to gain electrons in chemical reactions. 

As elements progress from group 13 to group 17, they show a shift from metallic characteristics to properties of the nonmetals, but the distinctions are not cut-and-dried. Some elements listed in groups 13, 14, 15, and 16 may have both metal-like qualities—metalloids or semiconductors—as well as a few nonmetal properties. 

Metalloid An element that exhibits some properties of metals and some properties of nonmetals. 

The semimetals, or metalloids, are known to exhibit some of the properties of metals and some of those of nonmetals. The semimetals are B, Si, Ge, As, Sb, Te, and At. They are highlighted in bold in the partial periodic table in Figure 4.1. The elements located to the left of the semimetals are the metals those to the right of the semimetals are the nonmetals. Identifying an element as a metal, nonmetal, or semimetal is important in identifying periodic trends and in identifying the types of bonds that atoms will form with each other. 

Metalloids Elements that exhibit some of the properties of metals and nonmetals. 

The color coding in the periodic table on pages 92 and 93 identifies which elements are metals (blue), nonmetals (yellow), and metalloids (green). The majority of the elements are metals. They occupy the entire left side and center of the periodic table. Nonmetals occupy the upper-right-hand corner. Metalloids are located along the boimdary between metals and non-metals. Each of these classes has characteristic chemical and physical properties, so by knowing whether an element is a metal, nonmetal, or metalloid, you can make predictions about its behavior. Elements are classified as metals, metalloids, or nonmetals on the basis of their physical and chemical properties. 

---