Question

Give the electron configuration for each of the following ions, and tell whether each is paramagnetic or diamagnetic. (a) \(\mathrm{Cr}^{3+}\) (c) \(\mathrm{Ni}^{2+}\) \((b) V^{2+}\) (d) \(\mathrm{Cu}^{+}\)

Short answer

(a) Paramagnetic, (b) Paramagnetic, (c) Paramagnetic, (d) Diamagnetic.

Step-by-step solution

Understand Electron Configurations

An electron configuration tells you how electrons are distributed among different atomic orbitals. When dealing with ions, remember that electrons are removed from the outermost shell first. We'll write the configuration for the neutral atom first, then adjust for the ion.

Find the Electron Configuration of Neutral Atoms

For each element, determine the electron configuration of the neutral atom:- Chromium (Cr): [Ar] 3d\(^5\) 4s\(^1\)- Vanadium (V): [Ar] 3d\(^3\) 4s\(^2\)- Nickel (Ni): [Ar] 3d\(^8\) 4s\(^2\)- Copper (Cu): [Ar] 3d\(^{10}\) 4s\(^1\)

Adjust for Ions

Subtract electrons for cations (positive ions).- \(\mathrm{Cr}^{3+}\): Lose 3 electrons: [Ar] 3d\(^3\)- \(\mathrm{V}^{2+}\): Lose 2 electrons: [Ar] 3d\(^3\)- \(\mathrm{Ni}^{2+}\): Lose 2 electrons: [Ar] 3d\(^8\)- \(\mathrm{Cu}^{+}\): Lose 1 electron: [Ar] 3d\(^{10}\)

Determine Magnetic Properties

Electrons with unpaired spins result in paramagnetism, while fully paired spins result in diamagnetism.- \(\mathrm{Cr}^{3+}\): [Ar] 3d\(^3\) - 3 unpaired electrons, so it is paramagnetic.- \(\mathrm{V}^{2+}\): [Ar] 3d\(^3\) - 3 unpaired electrons, so it is paramagnetic.- \(\mathrm{Ni}^{2+}\): [Ar] 3d\(^8\) - 2 unpaired electrons, so it is paramagnetic.- \(\mathrm{Cu}^{+}\): [Ar] 3d\(^{10}\) - 0 unpaired electrons, so it is diamagnetic.

Key concepts

Understanding Paramagnetism

Paramagnetism is a basic property of materials that are attracted by an external magnetic field. This attraction is due to the presence of unpaired electrons in the material's atomic structure. When electrons are unpaired, their spins do not cancel each other out, creating a net magnetic moment.

In the case of ions such as

• Cr3+
• V2+
• Ni2+

all of these have unpaired electrons. For example, Cr3+ and V2+ each have three unpaired electrons in their 3d orbitals. These unpaired electrons lead to a net magnetic moment.

Thus,

• atoms or ions with unpaired electrons are paramagnetic
• these particles will be attracted by a magnetic field

Remember, paramagnetism determines how substances react to magnetic fields by examining their electron configurations.

Examining Diamagnetism

Diamagnetism, on the other hand, occurs when all electrons in an atom or ion are paired. This results in a net magnetic moment of zero, because paired electrons have opposite spins that cancel each other out.

As a practical example, consider the ion Cu+. Its electron configuration is [Ar] 3d¹⁰, where all electrons are perfectly paired in the 3d sublevel.

Some important points about diamagnetism include:

• Diamagnetic materials do not retain magnetic properties when the external field is removed
• These materials are repelled by magnetic fields, although weakly Variations in electron pairing lead to

diable connections between different electron configurations. Diamagnetic materials react quite subtly, and they underlie more complex interactions in the magnetic field behavior of atoms.

The Role of Cations

Cations are positively charged ions that occur when an atom loses one or more electrons. This loss affects the electron configuration and consequently the magnetic properties of the atom.

When dealing with cations, like Cr3+ and Ni2+, remember:

• Electrons are generally lost from the outermost shell first as dictated by the principles of electron configuration
• This leads to fewer electrons in the d orbitals, affecting the number of unpaired electrons and hence the cation's magnetic property

Cations exhibit different configurations and therefore different magnetic or chemical properties compared to their neutral atoms. Understanding the behavior of electrons after ionization is key to assessing these changes.

Exploring Atomic Orbitals

Atomic orbitals describe regions in space where electrons are likely to be found. These are classified mainly by the principal quantum number (n) and are further organized by sublevels s, p, d, and f.

An electron's precise location in an atom is described by its orbital configuration. For instance,

• Chromium (Cr) as [Ar] 3d⁵ 4s¹
• Vanadium (V) as [Ar] 3d³ 4s²

In transitioned ions, like Cr3+, electrons are often removed from the 4s before the 3d orbitals, showcasing the stability associated with half-filled and filled sublevels.

Atomic orbitals' arrangement dictates how atoms bond and interact with each other. A sound understanding of these distributions prepares you for predicting and recognizing different element behaviors.