Textbook Question
The unit cell of nickel arsenide is shown here. (b) What is the empirical formula?
Ch.12 - Solids and Modern Materials
Chapter 12, Problem 32
For each of these solids, state whether you would expect it to possess metallic properties: (a) TiCl4 (b) NiCo alloy (c) W (d) Ge (e) ScN
Verified step by step guidance1
Step 1: Understand the nature of metallic properties. Metallic properties include high electrical and thermal conductivity, malleability, ductility, and a shiny appearance. These properties are typically found in metals and alloys.
Step 2: Analyze TiCl4. Titanium tetrachloride (TiCl4) is a molecular compound, not a metal. It consists of titanium and chlorine atoms bonded covalently, and it is typically a liquid at room temperature. Therefore, it does not exhibit metallic properties.
Step 3: Analyze NiCo alloy. An alloy is a mixture of two or more elements, where at least one is a metal. Nickel (Ni) and cobalt (Co) are both metals, and their alloy is expected to exhibit metallic properties such as conductivity and malleability.
Step 4: Analyze W. Tungsten (W) is a transition metal known for its high melting point and density. It exhibits typical metallic properties, including electrical conductivity and a shiny appearance.
Step 5: Analyze Ge and ScN. Germanium (Ge) is a metalloid, which means it has properties intermediate between metals and non-metals. It can exhibit some metallic properties under certain conditions. Scandium nitride (ScN) is a compound that can exhibit metallic properties due to its structure and bonding, similar to some metal nitrides.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Metallic Bonding
Metallic bonding occurs when metal atoms share their pooled electrons, allowing them to conduct electricity and heat. This type of bonding results in properties such as malleability, ductility, and luster, which are characteristic of metals. Understanding this concept helps in identifying whether a substance exhibits metallic properties based on its bonding structure.
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Chemical Bonds
Alloys
Alloys are mixtures of two or more elements, where at least one is a metal. They often exhibit enhanced properties compared to their constituent elements, such as increased strength or corrosion resistance. Recognizing that alloys like NiCo can possess metallic properties is crucial for evaluating the metallic nature of the given substances.
Semiconductors
Semiconductors are materials that have electrical conductivity between that of conductors and insulators. Elements like germanium (Ge) can exhibit properties of both metals and non-metals, depending on conditions such as temperature and doping. Understanding the behavior of semiconductors is essential for determining whether a substance like Ge possesses metallic properties.
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Related Practice
Textbook Question
The unit cell of a compound containing potassium, aluminum, and fluorine is shown here. (a) What type of lattice does this crystal possess (all three lattice vectors are mutually perpendicular)?
Textbook Question
Consider the unit cells shown here for three different structures that are commonly observed for metallic elements. (a) Which structure(s) corresponds to the densest packing of atoms?
Textbook Question
Consider the unit cells shown here for three different structures that are commonly observed for metallic elements. (b) Which structure(s) corresponds to the least dense packing of atoms?
Textbook Question
Sodium metal (atomic weight 22.99 g/mol) adopts a body-centered cubic structure with a density of 0.97 g/cm3. (a) Use this information and Avogadro’s number (NA = 6.022 × 1023/mol) to estimate the atomic radius of sodium. (b) If sodium didn't react so vigorously, it could float on water. Use the answer from part (a) to estimate the density of Na if its structure were that of a cubic close-packed metal. Would it still float on water?