Question

Which of the following metals have only one oxidation state? (a) \(\underline{V}\) (b) \(\mathrm{Al}\) (c) Co (d) Sc

Short answer

Both Al and Sc have only one oxidation state, +3.

Step-by-step solution

Understand what Oxidation States are

Oxidation states indicate the degree of oxidation of an atom in a compound. They represent the hypothetical charges that an atom would have if all bonds to atoms of different elements were 100% ionic.

List Common Oxidation States of Each Metal

For each metal, observe how many oxidation states they typically exhibit: - Vanadium (\(V\)) has multiple oxidation states, including +2, +3, +4, and +5.- Aluminum (\(Al\)) usually exhibits only a +3 oxidation state.- Cobalt (\(Co\)) commonly shows +2 and +3 oxidation states.- Scandium (\(Sc\)) almost exclusively shows a +3 oxidation state.

Determine Metals with Single Oxidation State

Identify which metals have only one consistent oxidation state:- Aluminum (\(Al\)) with only +3- Scandium (\(Sc\)) also with only +3

Key concepts

Metals

Metals are a class of elements known for their ability to conduct electricity and heat. They are usually shiny, ductile, and malleable. Common characteristics of metals include being solid at room temperature (with the exception of mercury), and having a high density. Metals are often involved in forming positive ions, known as cations, by losing electrons during chemical reactions.

Oxidation states are important for metals as they indicate the number of electrons a metal can lose or gain. This concept helps in understanding the metal's chemical behavior. Most metals have variable oxidation states, allowing them to form different compounds and partaking in a variety of chemical reactions.

Some metals, however, exhibit only a singular oxidation state, where they lose a fixed number of electrons during reactions. This helps predict their reactions more easily. The study of metals' oxidation states is crucial in fields like inorganic chemistry and materials science, providing insights into how metals interact with other substances.

Aluminum

Aluminum is a lightweight, silvery-white metal known for its remarkable resistance to corrosion. It is one of the most abundant elements in the Earth's crust, and is widely used in industries ranging from aerospace to kitchenware.

This metal is known for having a single oxidation state: +3. This means that in chemical reactions, aluminum typically loses three electrons, forming Al³⁺ ions. This fixed oxidation state contributes to its predictable chemical behavior, making it a valuable material for a variety of applications such as in alloys and as a lightweight, durable metal for manufacturing.

Being a metal with a single oxidation state simplifies its chemistry, as it only participates in reactions where three electrons are transferred. This predictability is beneficial in industries that rely on aluminum to produce consistent results in manufacturing and other processes.

Scandium

Scandium is a rare, silvery-white metal often classified with the transition metals. It was once considered a rare earth element because of its occurrence with them in the Earth's crust.

Like aluminum, scandium primarily exhibits a single oxidation state of +3. In chemical reactions, scandium exhibits a high tendency to lose three electrons and form Sc³⁺ ions. This results in highly consistent chemical behavior, as it does not have variable oxidation states like many other transition metals.

Despite its rarity, scandium is used in a variety of applications. It is often added to aluminum alloys to strengthen the material without adding significant weight, enhancing products such as bicycles, baseball bats, and aerospace components. The consistency of its single oxidation state is key to its use in these specific and high-performance applications.

Oxidation State Variability

Oxidation state variability refers to the ability of an element, especially metals, to exist in multiple oxidation states. This variability is common among transition metals, which have partially filled d orbitals that allow them to lose different numbers of electrons.

The oxidation states of metals can affect their color, magnetism, conductivity, and the types of chemical bonds they form. For example, vanadium is known for its colorful compounds, each corresponding to a different oxidation state (+2, +3, +4, +5). This variability is essential for the diverse roles these metals play in catalysis and electronic applications.

However, not all metals exhibit this trait. Metals like aluminum and scandium typically have a single oxidation state, which limits the compounds they can form. This lack of variability means their chemical behavior is more predictable, often making them more suitable for applications that require consistency and simplicity.