Textbook Question
Which of the following is the expected product of the reaction of K(s) and H2(g)? (i) KH(s), (ii) K2H(s), (iii) KH2(s), (iv) K2H2(s), or (v) K(s) and H2(g) will not react with one another.
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Ch.7 - Periodic Properties of the Elements
Chapter 7, Problem 108b
We will see in Chapter 12 that semiconductors are materials that conduct electricity better than nonmetals but not as well as metals. The only two elements in the periodic table that are technologically useful semiconductors are silicon and germanium. Integrated circuits in computer chips today are based on silicon. Compound semiconductors are also used in the electronics industry. Examples are gallium arsenide, GaAs; gallium phosphide, GaP; cadmium sulfide, CdS; and cadmium selenide, CdSe. (b) Workers in the semiconductor industry refer to 'II–VI' and 'III–V' materials, using Roman numerals. Can you identify which compound semiconductors are II–VI and which are III–V?
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Semiconductors
Semiconductors are materials that have electrical conductivity between that of insulators and conductors. They can conduct electricity under certain conditions, making them essential for electronic devices. Silicon and germanium are the most common elemental semiconductors, while compound semiconductors consist of two or more elements, such as gallium arsenide and cadmium sulfide.
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03:37
Metalloid Properties
Periodic Table Groups
The periodic table is organized into groups based on similar properties of elements. Group II elements (alkaline earth metals) and Group VI elements (chalcogens) combine to form II–VI semiconductors, while Group III (boron group) and Group V (pnictogens) elements form III–V semiconductors. Understanding these groupings helps identify the elemental composition of compound semiconductors.
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05:33Periodic Table: Group Names
Compound Semiconductors
Compound semiconductors are formed from two or more elements and exhibit unique electronic properties. They are often used in high-performance applications, such as LEDs and high-frequency devices. Examples include gallium arsenide (III–V) and cadmium selenide (II–VI), which are crucial for various electronic and optoelectronic applications.
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02:11Ionic Compounds Naming
Related Practice
Textbook Question
A historian discovers a nineteenth-century notebook in which some observations, dated 1822, were recorded on a substance thought to be a new element. Here are some of the data recorded in the notebook: 'Ductile, silver-white, metallic looking. Softer than lead. Unaffected by water. Stable in air. Melting point: 153 °C. Density: 7.3 g>cm3. Electrical conductivity: 20% that of copper. Hardness: About 1% as hard as iron. When 4.20 g of the unknown is heated in an excess of oxygen, 5.08 g of a white solid is formed. The solid could be sublimed by heating to over 800 °C.' (a) Using information in the text and the CRC Handbook of Chemistry and Physics, and making allowances for possible variations in numbers from current values, identify the element reported.
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Textbook Question
We will see in Chapter 12 that semiconductors are materials that conduct electricity better than nonmetals but not as well as metals. The only two elements in the periodic table that are technologically useful semiconductors are silicon and germanium. Integrated circuits in computer chips today are based on silicon. Compound semiconductors are also used in the electronics industry. Examples are gallium arsenide, GaAs; gallium phosphide, GaP; cadmium sulfide, CdS; and cadmium selenide, CdSe. (a) What is the relationship between the compound semiconductors' compositions and the positions of their elements on the periodic table relative to Si and Ge?
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Textbook Question
Moseley established the concept of atomic number by studying X rays emitted by the elements. The X rays emitted by some of the elements have the following wavelengths: Element Wavelength (pm) Ne 1461 Ca 335.8 Zn 143.5 Zr 78.6 Sn 49.1 (a) Calculate the frequency, n, of the X rays emitted by each of the elements, in Hz.
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Textbook Question
Moseley established the concept of atomic number by studying X rays emitted by the elements. The X rays emitted by some of the elements have the following wavelengths: Element Wavelength (pm) Ne 1461 Ca 335.8 Zn 143.5 Zr 78.6 Sn 49.1 (d) Use the result from part (b) to predict the X-ray wavelength emitted by iron.
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Textbook Question
Moseley established the concept of atomic number by studying X rays emitted by the elements. The X rays emitted by some of the elements have the following wavelengths: Element Wavelength (pm) Ne 1461 Ca 335.8 Zn 143.5 Zr 78.6 Sn 49.1 (e) A particular element emits X rays with a wavelength of 98.0 pm. What element do you think it is?