Problem 9 - An Introduction to Physical Science

Question

Choose the word or phrase that best answers the question. Which type of elements are semiconductors? A) metals B) nonmetals C) metalloids D) gases

Step-by-Step Solution

Answer

Metalloids

Step 1 - Review the definitions

Understand the basic definitions of each type of element: metals, nonmetals, metalloids, and gases. Metals are typically good conductors of electricity, nonmetals generally do not conduct electricity, metalloids have properties between metals and nonmetals, and gases are usually neither conductive nor solid at room temperature.

Step 2 - Recall properties of semiconductors

Semiconductors have electrical conductivity between that of a conductor and an insulator. They can conduct electricity under certain conditions, making them essential in electronics.

Step 3 - Identify the element type

Metalloids are known to have properties of both metals and nonmetals. Importantly, they include elements like silicon and germanium, which are famous semiconductors used in technology.

Step 4 - Choose the best answer

Given that metalloids possess the properties that characterize semiconductors, the best answer is option C) metalloids.

Key Concepts

Semiconductors

Semiconductors are materials that have electrical conductivity between that of a conductor (like metals) and an insulator (like nonmetals). This unique property allows them to conduct electricity under specific conditions, such as the application of voltage or exposure to light. Semiconductors are the backbone of modern electronics, including computers, smartphones, and solar cells. Key semiconductor materials include silicon and germanium. These elements are crucial in manufacturing devices like transistors and diodes, which are essential for the functioning of various electronic circuits and systems.

Metalloids

Metalloids are elements with properties that are intermediate between those of metals and nonmetals. On the periodic table, metalloids typically border the staircase line. They have a mixed set of characteristics, which makes them incredibly versatile. For example, they might exhibit metallic lustre (appearance), but they are brittle like nonmetals. Metalloids are significant because they include elements like silicon and germanium, which are famous for their semiconductor properties. This makes metalloids indispensable in the field of microelectronics and advanced technology.

Electrical Conductivity

Electrical conductivity is the ability of a material to allow the flow of electric current. Conductivity varies significantly among different materials:

• Metals, like copper and aluminum, are excellent conductors due to their free-moving electrons.
• Nonmetals, such as sulfur and phosphorus, are generally poor conductors because they lack free-moving charge carriers.
• Semiconductors have a moderate level of conductivity that can be manipulated by introducing impurities (doping) or by changing the temperature, light exposure, or electric field.

The ability to control and change their conductivity underlines the importance of semiconductors in electronic devices and systems.

Properties of Elements

Different elements on the periodic table have various properties that categorize them as metals, nonmetals, metalloids, or gases. Understanding these properties helps in predicting the behavior and potential uses of the elements:

• Metals: Generally have high electrical and thermal conductivity, malleability, ductility, and a lustrous appearance.
• Nonmetals: Typically poor conductors, not malleable or ductile, and may be gases, liquids, or brittle solids at room temperature.
• Metalloids: Exhibit mixed properties and are often semiconductors, making them vital in electronic applications.
• Gases: Most are poor conductors, neither solid nor conductive at room temperature, and have low density compared to solid or liquid elements.

Knowing these properties allows scientists and engineers to select the right materials for specific applications, particularly in electronics and technology.