Question

For each of these solids, state whether you would expect it to possess metallic properties: (a) TiCl_ \(_{4},(\mathbf{b})\) NiCo alloy, \((\mathbf{c}) \mathrm{W}\) \((\mathbf{d}) \mathrm{Ge},(\mathbf{e}) \mathrm{ScN}\)

Short answer

In summary, out of the given solids, NiCo alloy \((b)\) and tungsten (W) \((c)\) are expected to possess metallic properties. However, TiCl_4 \((a)\), Germanium (Ge) \((d)\), and Scandium nitride (ScN) \((e)\) do not fully possess metallic properties.

Step-by-step solution

a) TiCl_4

Titanium tetrachloride is a compound formed between a transition metal (Ti) and a non-metal (Cl). This compound is more likely to exhibit ionic or covalent characteristics than metallic properties due to the nature of the bond between the metal and non-metal. As a result, we do not expect TiCl_4 to possess metallic properties.

b) NiCo alloy

NiCo is an alloy containing two transition metals - nickel (Ni) and cobalt (Co). Alloys of metals generally have metallic properties since they contain a mix of metallic elements that share a metallic bond. Therefore, we expect the NiCo alloy to possess metallic properties.

c) W

Tungsten (W) is a transition metal known for its high strength and good electrical conductivity. As a metal, it inherently has metallic properties. Thus, we expect tungsten to possess metallic properties.

d) Ge

Germanium (Ge) is a metalloid, which means that it has properties of both metals and non-metals. While it does exhibit some metallic properties like having a shiny appearance and being a good conductor of electricity, it is not considered a full-fledged metal. Since the question asks for solids that possess metallic properties, we can conclude that Germanium does not fully possess metallic properties.

e) ScN

Scandium nitride (ScN) is a compound formed between a transition metal (Sc) and a non-metal (N). Similar to TiCl_4, this compound is more likely to exhibit ionic or covalent characteristics rather than metallic properties due to the nature of the bond between the metal and non-metal. Therefore, we do not expect ScN to possess metallic properties. In summary, out of the given solids, NiCo alloy and tungsten (W) are expected to possess metallic properties, while the other three solids (TiCl_4, Ge, and ScN) do not fully possess metallic properties.

Key concepts

Transition Metals

Transition metals are fascinating elements found in the center of the periodic table, specifically in the d-block. They are known for their high melting points, the ability to form various oxidation states, and conducting electricity well.
They include well-known metals such as iron, copper, tungsten, and nickel.
A key feature of transition metals is their incomplete d-subshells in one or more of their typical oxidation states. This means they can lose different numbers of electrons, allowing them to form a variety of compounds.
Moreover, transition metals are often used in industrial applications due to their durability and strength.

• They have high electrical conductivity
• Their compounds are often colorful
• They are essential in many catalysts

Metallic Bonding

Metallic bonding is a type of chemical bond that holds the atoms together in a metal. It is a result of the attraction between positively charged metal ions and the electrons that move freely around them.
This is why metals are excellent conductors of electricity. The free electrons allow electrical currents to pass through easily.
Metallic bonds give metals their characteristic properties. These include malleability, where metals can be hammered into thin sheets, and ductility, meaning they can be drawn into wires.

• They provide metals with their shiny appearance
• Make metals good conductors of heat
• Allow metals to be reshaped without breaking

Alloys

Alloys are mixtures of two or more elements, where the primary component is a metal. They have distinct properties that are often superior to those of their individual components. For example, alloys like stainless steel and brass are more durable than pure metals.
Alloys are made to improve strength, prevent corrosion, or reduce costs.
Transition metals often form the basis for useful alloys, such as the NiCo alloy, which combines nickel and cobalt.
These combinations make alloys suitable for various industrial applications, particularly where strength and durability are crucial.

• More resistant to corrosion than pure metals
• Can have lower melting points
• Often stronger and harder than metals

Metalloids

Metalloids, also referred to as semimetals, have properties that are intermediate between metals and non-metals. They are found along the zig-zag line on the periodic table.
Germanium and silicon are common examples. These elements can conduct electricity better than non-metals, but not as well as metals, making them useful in semiconductors and electronics.
Metalloids also exhibit a shiny, metallic appearance. Yet, unlike true metals, they are not entirely malleable or ductile. This makes metalloids unique, as they display a mixture of properties from both categories.

• Form alloys with metals
• Useful in optical and electronic devices
• Show varied chemical behavior