Question

Without referring to Figure 24.1 , state whether each of the following elements are metals, metalloids, or nonmetals: (a) \(\mathrm{Cs},(\mathrm{b}) \mathrm{Ge},(\mathrm{c}) \mathrm{I},(\mathrm{d}) \mathrm{Kr},(\mathrm{e}) \mathrm{W},(\mathrm{f}) \mathrm{Ga},\) (g) \(\mathrm{Te},(\mathrm{h}) \mathrm{Bi}\).

Short answer

(a) Metal, (b) Metalloid, (c) Nonmetal, (d) Nonmetal, (e) Metal, (f) Metal, (g) Metalloid, (h) Metal.

Step-by-step solution

Identify Group and Period

Determine the group and period of each element on the periodic table. This helps identify whether the element is in a region typically occupied by metals, nonmetals, or metalloids.

Determine Element Category

Based on the group and period location in the periodic table determine the type of the element: metal, metalloid, or nonmetal. Metals are usually on the left and center, nonmetals are on the right (except hydrogen), and metalloids lie between them.

Assign Category for Each Element

Evaluate each given element: (a) Cs is in Group 1, period 6, therefore it is a **metal**. (b) Ge is in Group 14, period 4, therefore it is a **metalloid**. (c) I is in Group 17, period 5, therefore it is a **nonmetal**. (d) Kr is in Group 18, period 4, therefore it is a **nonmetal**. (e) W is in Group 6, period 6, therefore it is a **metal**. (f) Ga is in Group 13, period 4, therefore it is a **metal**. (g) Te is in Group 16, period 5, therefore it is a **metalloid**. (h) Bi is in Group 15, period 6, therefore it is a **metal**.

Key concepts

Metals

Metals are elements that are commonly found on the left side and in the center of the periodic table. These elements are characterized by their shiny appearance and great ability to conduct both heat and electricity. They are usually solid at room temperature, with mercury being a notable exception as a liquid metal. Metals tend to lose electrons easily, forming positive ions.

Some well-known properties of metals include:

• High density and melting points
• Malleability, meaning they can be hammered into thin sheets
• Ductility, allowing them to be drawn into wires
• Good thermal and electrical conductivity

These properties make metals essential for a wide range of applications, from construction materials to electronic devices. Examples of metals from the given exercise include cesium (Cs), tungsten (W), gallium (Ga), and bismuth (Bi).

Metalloids

Metalloids, also known as semimetals, are elements that have properties intermediate between metals and nonmetals. They are typically positioned along the zig-zag line on the periodic table. This line separates metals and nonmetals. Metalloids exhibit mixed properties that can be useful in various applications, particularly in the electronics industry.

Characteristics of metalloids include:

• Semiconductive abilities which mean they can conduct electricity better than nonmetals but not as well as metals
• The ability to form alloys with metals
• Variable reactivity depending on the other elements they interact with

Because of their semiconductive nature, metalloids such as germanium (Ge) and tellurium (Te) are pivotal in making electronic components like transistors and diodes.

Nonmetals

Nonmetals are found on the right side of the periodic table. These elements exhibit properties starkly different from those of metals. Nonmetals can be solids, liquids, or gases at room temperature, and they do not conduct heat or electricity well. Their appearances can vary, but they generally lack the shiny luster of metals.

Key properties of nonmetals are:

• Brittleness in solid state, meaning they easily break or shatter
• Poor conductivity of heat and electricity
• Lower densities and melting points compared to metals
• Tendency to gain electrons during chemical reactions, forming negative ions

Nonmetals play vital roles in organic compounds and biological processes. In the exercise, iodine (I) and krypton (Kr) were identified as nonmetals.

Element Categories

Element categories in the periodic table classify elements based on their similar properties and reactive behaviors. The main categories are metals, nonmetals, and metalloids, each positioned distinctly across the periodic table.

Key aspects of element categories include:

• Metals are generally located on the left and center of the table.
• Nonmetals are typically on the far right side, except for hydrogen, which is at the top of the table.
• Metalloids straddle the boundary between metals and nonmetals, forming a zig-zag pattern.

Understanding these categories helps predict the general properties and potential chemical behavior of an element. This classification is fundamental to grasping the vast array of chemical reactions and material uses. Recognizing which category an element belongs to streamlines studying and application of chemistry in real-world settings.