Question

'The group 12 metals differ significantly from the \(d\) -block metals in groups \(4-11\) '. Discuss this statement.

Short answer

Group 12 metals differ from groups 4-11 by having completely filled d orbitals, lower reactivity, and distinct physical properties.

Step-by-step solution

Identify Group 12 Metals

Group 12 of the periodic table includes the metals Zinc (Zn), Cadmium (Cd), and Mercury (Hg). These are known for having completely filled d-orbitals in their elemental form and typical oxidation states. They exhibit +2 oxidation state predominantly.

Characteristics of Group 3-11 Metals

The metals in groups 4-11 are transition metals. They usually have partially filled d orbitals and exhibit a variety of oxidation states. This partial filling of d orbitals is what gives them their unique properties such as forming colored compounds and having magnetic properties.

Compare Electron Configurations

Group 12 metals have the electron configuration of ext{(n-1)d}^{10} ext{ns}^{2}, meaning their d-orbitals are fully filled, while group 4-11 metals have ext{(n-1)d}^x ext{ns}^2, where x varies from 1 to 10, indicating partially filled d-orbitals.

Discuss Chemical Properties

Group 12 metals are typically less reactive compared to transition metals, which often engage in complex formation due to vacant d orbitals. Furthermore, they have lower melting and boiling points than most transition metals.

Discuss Physical Properties

In terms of physical properties, group 12 metals tend to be softer and have a lower density compared to their transition metal counterparts.

Key concepts

Group 12 Metals

Group 12 of the periodic table consists of three significant metals: Zinc (Zn), Cadmium (Cd), and Mercury (Hg). These metals are distinct from the typical transition metals found in groups 3-11. One of the defining characteristics of Group 12 metals is their full d-orbital in their elemental state. Unlike many other metals in the d-block, they have a characteristic electron configuration with complete d-subshells.
Interestingly, while these Group 12 metals exhibit +2 oxidation states prominently, they do not show a diverse range of oxidation states like their group 3-11 counterparts. Due to this characteristic, their reactivity is relatively lower, and they don't show the diverse chemical behavior typical of transition metals. The filled d-orbitals lead to a reduction in the ability to form colored compounds or show magnetic properties, traits often associated with partially filled d-orbitals in other transition metals.

Electron Configuration

Electron configuration plays a vital role in determining the chemical nature of an element. For Group 12 metals, their electron configuration stands out as \[(n-1)d^{10}ns^2\]. This configuration indicates that the d-orbitals are fully filled.
For example, Zinc has the electron configuration [Ar] 3d\(^{10}\) 4s\(^{2}\), Cadmium is [Kr] 4d\(^{10}\) 5s\(^{2}\), and Mercury is [Xe] 4f\(^{14}\) 5d\(^{10}\) 6s\(^{2}\).
This fully filled d-subshell contributes to their lack of variable oxidation states and limits their ability to form complex compounds as compared to the metals in groups 4-11, which often have the general configuration \[(n-1)d^x ns^2\], allowing for the presence of unpaired electrons. These unpaired electrons make group 3-11 metals more chemically versatile.

Oxidation States

Oxidation states are critical for understanding how metals interact in chemical reactions. In the case of Group 12 metals, they predominantly exhibit a +2 oxidation state. The presence of a fully filled d-subshell (\((n-1)d^{10}\)) decreases their ability to participate in further electron exchange reactions, limiting their oxidation states.
For instance, Zinc commonly forms Zn\(^{2+}\) ions, Cadmium forms Cd\(^{2+}\), and Mercury tends to form Hg\(^{2+}\). This simplicity in oxidation states contrasts with groups 4-11, where metals can exhibit multiple oxidation states due to the presence of vacant sites in their d-orbitals for electron exchange.
This limited oxidation capability in Group 12 is part of why they do not participate in forming complex ions as readily as other transition metals.

Chemical Properties of Metals

The chemical properties of metals are defined by their electron configurations and oxidation states. Group 12 metals have unique chemical characteristics due to their fully filled d-orbitals. They are generally less reactive than other transition metals because they don't need to fulfill the electron-wanting nature of partially filled d-orbitals.
Due to this filled state, Group 12 metals like Zinc, Cadmium, and Mercury are more stable and form fewer complexes with ligands compared to other transition metals. They also show less ability to form colorful compounds or exhibit magnetic properties.
Furthermore, these metals tend to have lower melting and boiling points, making them distinctive in their class. For example, Mercury is liquid at room temperature, a rare property for metal, highlighting its unique placement in Group 12.