Question

a. Classify the following elements as metals or nonmetals: $$ \begin{array}{lll} \mathrm{Mg} & \mathrm{Si} & \mathrm{Rn} \\ \mathrm{Ti} & \mathrm{Ge} & \mathrm{Eu} \\ \mathrm{Au} & \mathrm{B} & \mathrm{Am} \\ \mathrm{Bi} & \mathrm{At} & \mathrm{Br} \end{array} $$ b. The distinction between metals and nonmetals is really not a clear one. Some elements, called metalloids, are intermediate in their properties. Which of these elements would you reclassify as metalloids? What other elements in the periodic table would you expect to be metalloids?

Short answer

The given elements can be classified as follows: Metals: Mg, Ti, Eu, Au, Am, Bi Nonmetals: Rn, At, Br Metalloids: Si, Ge, B Other elements in the periodic table that are considered metalloids include: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), and Polonium (Po).

Step-by-step solution

Identify the elements' positions in the periodic table

In order to classify the given elements, first, refer to a periodic table and identify the position of the following elements within the periodic table: Mg, Si, Rn, Ti, Ge, Eu, Au, B, Am, Bi, At, Br

Classify the elements as metals or nonmetals

Based on their positions in the periodic table and the general properties of the groups they belong to, classify the given elements as follows: Metals: Mg, Ti, Eu, Au, Am, Bi Nonmetals: Si, Rn, B, At, Br

Identify metalloids in the given set of elements

Elements with properties between metals and nonmetals are considered as metalloids. Based on their properties and their position in the periodic table, identify the following elements as metalloids: Si, Ge, B

List other elements in the periodic table expected to be metalloids

Other elements in the periodic table that could be considered as metalloids are: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), and Polonium (Po). These elements are typically found around the diagonal line separating metals and nonmetals in the p-block region of the periodic table and have properties that are intermediate between metals and nonmetals. Final classification of the given elements: Metals: Mg, Ti, Eu, Au, Am, Bi Nonmetals: Rn, At, Br Metalloids: Si, Ge, B

Key concepts

Periodic Table Classification

Understanding the organization of the periodic table is crucial for classifying elements as metals, nonmetals, or metalloids. The periodic table is divided into several blocks referred to as s, p, d, and f-blocks. The metals reside on the left side of the periodic table and are characterized by their shiny appearance, malleability, ductility, and excellent heat and electricity conduction. Nonmetals, located on the right side, are often dull, brittle, and poor conductors of heat and electricity. Metalloids can be found bordering the staircase line that diagonally divides metals and nonmetals in the p-block.

Metallic character decreases as you move from left to right across a period and from bottom to top across a group. This is because of the increase in the number of valence electrons, which affects an element's ability to lose or gain electrons. When working through homework problems or classifying elements, pay special attention to the position of the element within the periodic table, as this is a strong indicator of its classification. For instance, Magnesium (Mg) as an s-block element is thus classified as a metal, whereas Radon (Rn), found in the p-block and to the far right, is classified as a nonmetal.

Properties of Metals and Nonmetals

Metals and nonmetals exhibit distinctive properties which help in their classification. Metals are typically hard, have high melting and boiling points, and are good conductors of electricity and heat. They tend to lose electrons during chemical reactions, forming positive ions or cations. In contrast, nonmetals usually have lower densities, melting and boiling points, and are mostly poor conductors, making them good insulators. They have a tendency to gain electrons, forming negative ions or anions.

For example, Gold (Au), with its high conductivity and ability to be drawn into wires, clearly fits the profile of a metal. Bromine (Br), on the other hand, is a liquid at room temperature and is known to gain electrons during reactions, which is indicative of its nonmetallic nature. It's important, while studying elements, to look at these properties, which are often defined by their electron configurations and bonds they form. Real-world examples, such as copper wiring (metal) or the use of sulfur in fertilizers (nonmetal), can solidify the understanding of these properties.

Identifying Metalloids

Metalloids exhibit a mix of metallic and nonmetallic properties, which can make them quite versatile. They are semiconductors, meaning they can carry electricity better than nonmetals but not as well as metals. This makes them useful in electronic devices. Metalloids also have a variable appearance and may not be as malleable or ductile as metals.

For instance, Silicon (Si) is a classic metalloid used extensively in computer chips for its semiconducting properties. When identifying metalloids in homework exercises or in practice, look for elements that have intermediate electronegativity and ionization energies. As demonstrated in the step-by-step solution, Boron (B) and Germanium (Ge) are also metalloids due to their properties and position on the periodic table near the metal-nonmetal dividing line. Typically, to correctly identify metalloids, you'll need to be familiar with their position in the periodic table and their unique mixed properties. This knowledge can be applied to predict the behavior of elements in chemical reactions and their use in various applications.