Problem 105 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following d-block elements do not posses characteristics properties of transition elements? (a) Cadmium (b) Manganese (c) Zinc (d) Copper

Step-by-Step Solution

Answer

Cadmium and Zinc do not exhibit typical transition metal properties.

Step 1: Understand the Characteristics of Transition Elements

Transition elements are d-block elements that typically have partially filled d-orbitals. This partially filled d-orbital is responsible for their ability to form various oxidation states, colored compounds, and exhibit paramagnetism.

Step 2: Identify Elements with Filled d-Orbitals

Elements that don't possess the characteristics of transition metals usually have completely filled d-orbitals in their common oxidation states. Cadmium, Zinc, and Copper fall into this situation in their most stable forms.

Step 3: Analyze Each Option

(a) Cadmium has the electronic configuration [Kr]4d^{10}5s^2, with a filled 4d orbital. (b) Manganese has the electronic configuration [Ar]3d^{5}4s^2 and has partially filled d-orbitals in its common +2 and +7 oxidation states. (c) Zinc has the electronic configuration [Ar]3d^{10}4s^2, with fully filled d-orbitals. (d) Copper has [Ar]3d^{10}4s^1 in its +1 oxidation state, also a filled d-orbital.

Step 4: Determine Which Elements Do Not Exhibit Transition Metal Characteristics

Since Cadmium ([Kr]4d^{10}5s^0) and Zinc ([Ar]3d^{10}4s^0) have filled d-orbitals, they do not exhibit typical transition metal characteristics like varying oxidation states or colored compounds.

Key Concepts

d-block elements

The d-block elements represent a group of elements in the periodic table that have electrons filling the d-orbitals. These elements are found in groups 3-12 and are commonly known as the transition metals. Transition metals are characterized by their ability to form various oxidation states and their partially filled d-orbitals, which contribute to their unique properties. However, not all d-block elements exhibit the typical transition metal characteristics. Some, such as Cadmium and Zinc, have completely filled d-orbitals in their most stable oxidation states, which affects their chemical behavior and often leads to them lacking some of these typical properties.

• Located in groups 3-12 of the periodic table
• Characterized by the filling of d-orbitals
• Includes well-known transition metals like Iron, Copper, and Nickel

Transition metals are highly valuable due to their ability to form complex ions, colored compounds, and their magnetic properties, creating broad industrial and technological applications.

oxidation states

Oxidation states refer to the charge of the central atom within a molecule or compound, often represented by integers that can be positive, negative, or zero. Transition metals are particularly notable for their ability to exist in multiple oxidation states. This versatility is primarily due to the d-orbitals, which allow electrons to be added or removed to form various states.

• Variable oxidation states are typical for transition metals, such as Iron which can be +2 or +3.
• Manganese can exhibit multiple oxidation states like +2, +3, +4, +6, and +7 due to its d-orbital configuration.

These varying oxidation states are key to understanding the chemistry of transition metals and their reactivity. They influence the type of bonds formed, the metal's participation in redox reactions, and its ability to form complexes, thereby broadening the range of chemical reactions these metals can participate in.

d-orbitals

The d-orbitals are a group of five orbitals (dₓᵧ, dₓ₂₋ᵧ₂, dₓᵤ, dᵧᵤ, and d𝓏²) found in atoms starting with the fourth period of the periodic table. These orbitals play a fundamental role in determining the chemical and physical properties of transition metals. Partially filled d-orbitals allow transition elements to exhibit properties such as multiple oxidation states and colorful compounds.

• Found in the middle of the electron configuration, after s and before p orbitals.
• Carry a maximum of 10 electrons in their five orbitals.

The filling and overlap of these d-orbitals enable transition metals to engage easily in complex formation, showcasing unique colors and magnetic properties in compounds. Elements like Chromium, which often have half-filled d-orbitals, exemplify intense coloration and the ability to transfer electrons in chemical processes due to these unique orbital characteristics.

paramagnetism

Paramagnetism is a form of magnetism that occurs only in the presence of an externally applied magnetic field. Transition elements often exhibit paramagnetism due to the presence of unpaired electrons in their d-orbitals. This characteristic is evident in many transition metals, which enhances their utility in various technological applications.

• Arises from unpaired electrons that create magnetic dipoles aligned in a magnetic field.
• Stronger than diamagnetism but weaker than ferromagnetism.

Because d-block elements usually have unpaired electrons in their d-orbitals, they are generally paramagnetic. Manganese, for instance, with its half-filled d-orbital configuration, often displays significant paramagnetic properties. This property impacts their interaction with magnetic fields and is exploited in techniques like magnetic resonance imaging (MRI).