Which solid would you expect to have the largest band gap? a. As(s) b. Sb(s) c. Bi(s)

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Understand the concept of band gap: The band gap is the energy difference between the valence band and the conduction band in a solid. A larger band gap means the material is more of an insulator, while a smaller band gap indicates a semiconductor or conductor.

Consider the position of elements in the periodic table: Arsenic (As), Antimony (Sb), and Bismuth (Bi) are in the same group (Group 15) and are arranged in order of increasing atomic number.

Recognize the trend in band gap across the periodic table: Generally, as you move down a group in the periodic table, the band gap tends to decrease because the atomic size increases, leading to more overlap of atomic orbitals and thus a smaller energy gap.

Apply the trend to the given elements: Since As, Sb, and Bi are in the same group, the band gap is expected to decrease from As to Bi.

Conclude which element has the largest band gap: Based on the trend, As(s) is expected to have the largest band gap among the three elements.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Band Gap

The band gap is the energy difference between the valence band and the conduction band in a solid material. It determines the electrical conductivity of the material; a larger band gap typically indicates that the material is an insulator or semiconductor, while a smaller band gap suggests metallic properties. Understanding band gaps is crucial for predicting how materials will behave in electronic and optical applications.

Semiconductors and Insulators

Semiconductors are materials that have a moderate band gap, allowing them to conduct electricity under certain conditions, such as increased temperature or doping. Insulators, on the other hand, have large band gaps, preventing the flow of electricity under normal conditions. The classification of materials based on their band gaps is essential for applications in electronics, photovoltaics, and optoelectronics.

Trends in Group 15 Elements

The elements arsenic (As), antimony (Sb), and bismuth (Bi) belong to Group 15 of the periodic table, which shows trends in properties such as atomic size and electronegativity. As you move down the group, the band gap generally decreases due to increased atomic size and decreased electronegativity, affecting the overlap of atomic orbitals. Recognizing these trends helps in predicting the electronic properties of these elements.