The Periodic Table Metals, Nonmetals, and Metalloids

Imagine, however, that three-quarters of the class members weigh 100 pounds each, and the other quarter weigh 200 pounds each. Now, the average weight would be 

We can express the fractions in this calculation in decimal form  

In such a calculation, the value (in this case, the weight) of each thing (people, atoms) is multiplied by the fraction of things that have that value. In Example 4-2 we expressed each percentage as a decimal fraction, such as 

Example 4-3 shows how the process can be reversed. Isotopic abundances can be calculated from isotopic masses and from the atomic weight of an element that occurs in nature as a mixture of only two isotopes. 

The atomic weight of gallium is 69.72 amu. The masses of the naturally occurring isotopes are 68.9257 amu for Ga and 70.9249 amu for Ga. Calculate the percent abundance of each isotope. 

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The Periodic Table Metals, Nonmetals, and Metalloids 4-2 Aqueous Solutions An Introduction... 

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

Another way to look at the periodic table is to divide the elements into metals, nonmetals, and metalloids. Most of the elements in the table are metals. Metals are usually shiny and can be bent, hammered, or pulled into many different shapes without breaking into pieces. Metals are also good conductors, which means that heat and electricity can pass through them easily. Metals tend to give up electrons when they react with other elements. From this information, one could guess that most metals are found on the left side of the table, where the valence electron shells are mostly empty. 

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 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. 

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. 

FIGURE J.3 The location of acidic, amphoteric, and basic oxides in the main groups of the periodic table. Metals form basic oxides, nonmetals form acidic oxides. The diagonal band of amphoteric oxides closely matches the diagonal band of metalloids (recall Fig. B.18). 

Metals are located on the left side of the periodic table. Metals tend to form cations, are generally ductile and malleable, and are good electrical and thermal conductors. Nonmetals are located on the right side of the periodic table. Nonmetals tend to form anions and have a wide variety of physical properties. Metalloids look like metals but have electrical conductivity intermediate between metals and nonmetals. For this reason, metalloids are called semiconductors. 

The first step in being able to use the information contained in the periodic table is to understand how it is arranged. Most periodic tables are similar to one another but to lessen confusion the periodic table shown in Figure 1 will be used. One of the first things that stands out is that the table is composed of metals, nonmetals, and metalloids. 

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. 

Sketch a simplified version of the periodic table and indicate the location of groups, periods, metals, nonmetals, and metalloids. 

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. 

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. 

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. 

Examine Figure 4.12, which shows the division of the periodic table into metals, nonmetals, and metalloids. Use what you know about electron configurations to explain these divisions. 96. Examine Figure 4.14, which shows the elements that form predictable ions. Use what you know about electron configurations to explain these trends. 

The elements in the periodic table can be classified even more broadly as metals, nonmetals, and metalloids, as shown in Figure 3-17. Metals tend toward... 

The elements can be classified as metals, nonmetals, metalloids, and noble gases. These classes occupy different areas of the periodic table. Metals tend to be shiny, malleable, and ductile and tend to be good conductors. Nonmetals tend to be brittle and tend to be poor conductors. 

In Section 4.2, we identified elements as metals, nonmetals, and metalloids. An element that has metallic character is an element that loses valence electrons easily. Metallic character is more prevalent in the elements (metals) on the left side of the periodic table and decreases going from left to right across a period. The elements (nonmetals) on the right side of the periodic table do not easily lose electrons, which means they are less metallic. Most of the metalloids between the metals and nonmetals tend to lose electrons, but not as easily as the metals. Thus, in Period 3, sodium, which loses electrons most easily, would be the most metallic. Going across from left to right in Period 3, metallic character decreases to argon, which has the least metallic character. 

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