Which Of The Following Atoms Is Diamagnetic

Which of the Following Atoms is Diamagnetic? Understanding Electron Configuration and Magnetic Properties

Determining whether an atom is diamagnetic or paramagnetic hinges on understanding its electron configuration and the behavior of its electrons within orbitals. This article delves into the fundamental concepts, explains how to determine magnetic properties, and provides a step-by-step guide to identifying diamagnetic atoms. We'll cover various examples and explore the underlying principles thoroughly.

Understanding Diamagnetism and Paramagnetism

Before we dive into specific atoms, let's clarify the key concepts:

Diamagnetism: This property arises when all electrons in an atom are paired. Paired electrons have opposite spins, effectively cancelling out each other's magnetic moments. As a result, diamagnetic substances are weakly repelled by external magnetic fields. They don't possess a permanent magnetic moment.

Paramagnetism: This occurs when an atom has unpaired electrons. These unpaired electrons possess individual magnetic moments that can align with an external magnetic field, resulting in a net magnetic moment. Paramagnetic substances are weakly attracted to external magnetic fields.

Ferromagnetism: While not directly related to our central question, it's important to note that ferromagnetism is a much stronger form of magnetism, seen in materials like iron, where the magnetic moments of numerous atoms align spontaneously. This is a cooperative phenomenon involving interactions between multiple atoms and is not exhibited by individual atoms.

Determining Magnetic Properties from Electron Configuration

The key to determining whether an atom is diamagnetic or paramagnetic lies in its electron configuration. This configuration details the arrangement of electrons within different energy levels and sublevels (s, p, d, f). We use the Aufbau principle, Hund's rule, and the Pauli exclusion principle to determine the electronic structure:

• Aufbau Principle: Electrons fill orbitals starting from the lowest energy level to the highest.
• Hund's Rule: Electrons will individually occupy each orbital within a subshell before doubling up in any one orbital. This maximizes the total spin.
• Pauli Exclusion Principle: No two electrons in the same atom can have the same set of four quantum numbers (n, l, ml, ms). This means that each orbital can hold a maximum of two electrons with opposite spins.

By understanding these rules, we can systematically fill orbitals with electrons and ascertain whether any unpaired electrons remain.

Step-by-Step Guide to Identifying Diamagnetic Atoms

Let's use a systematic approach to determine the magnetic properties of various atoms:

1. Determine the Atomic Number: Find the atomic number (number of protons) of the atom from the periodic table. This also represents the number of electrons in a neutral atom.

2. Write the Electron Configuration: Use the Aufbau principle to systematically fill electron orbitals. Remember the order of filling: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p...

3. Apply Hund's Rule: Ensure each orbital within a subshell is singly occupied before pairing electrons.

4. Check for Unpaired Electrons: Examine the electron configuration. If all electrons are paired (each orbital has two electrons with opposite spins), the atom is diamagnetic. If there are any unpaired electrons, the atom is paramagnetic.

Examples: Identifying Diamagnetic Atoms

Let's work through some examples:

Example 1: Helium (He)

• Atomic Number: 2
• Electron Configuration: 1s²
• Analysis: Both electrons are in the 1s orbital and are paired. Therefore, Helium is diamagnetic.

Example 2: Neon (Ne)

• Atomic Number: 10
• Electron Configuration: 1s²2s²2p⁶
• Analysis: All electrons are paired (1s orbital has two electrons, 2s orbital has two electrons, and each of the three 2p orbitals has two electrons). Therefore, Neon is diamagnetic.

Example 3: Beryllium (Be)

• Atomic Number: 4
• Electron Configuration: 1s²2s²
• Analysis: All electrons are paired. Therefore, Beryllium is diamagnetic.

Example 4: Oxygen (O)

• Atomic Number: 8
• Electron Configuration: 1s²2s²2p⁴
• Analysis: The 2p subshell has four electrons. According to Hund's rule, two electrons will occupy separate orbitals with parallel spins, and two will pair up in the third orbital. This leaves two unpaired electrons. Therefore, Oxygen is paramagnetic, not diamagnetic.

Example 5: Zinc (Zn)

• Atomic Number: 30
• Electron Configuration: [Ar] 3d¹⁰4s²
• Analysis: All electrons are paired. The filled 3d subshell and the filled 4s subshell both have all their electrons paired. Therefore, Zinc is diamagnetic.

Example 6: Argon (Ar)

• Atomic Number: 18
• Electron Configuration: [Ne] 3s²3p⁶
• Analysis: All orbitals are completely filled with paired electrons. Therefore, Argon is diamagnetic.

Example 7: Copper (Cu)

• Atomic Number: 29
• Electron Configuration: [Ar] 3d¹⁰4s¹ (exception to Aufbau principle)
• Analysis: While typically we expect 3d⁹4s², Copper exhibits an anomaly. The fully filled 3d¹⁰ subshell is more stable. This leaves one unpaired electron in the 4s orbital. Therefore, Copper is paramagnetic.

Advanced Considerations: Ions and Transition Metals

The examples above focused on neutral atoms. However, the principles extend to ions. When an atom loses or gains electrons to become an ion, its electron configuration changes, and its magnetic properties may change accordingly.

Transition metals, with their partially filled d orbitals, often present more complex cases. The subtle interplay between electron-electron repulsions and ligand field effects can affect the exact electron configuration and the presence of unpaired electrons. Predicting the exact magnetic properties of transition metal complexes requires advanced concepts in coordination chemistry.

Conclusion: Diamagnetism and Its Importance

Understanding diamagnetism is crucial in various fields, including:

• Materials Science: Diamagnetic materials have applications in superconducting magnets and magnetic levitation.
• Medical Imaging: Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) rely on the interaction of magnetic fields with atomic nuclei, with diamagnetic shielding playing a role in the observed signals.
• Chemical Analysis: Magnetic susceptibility measurements can be used to identify the presence of unpaired electrons and therefore determine the oxidation states of metals in compounds.

By following the steps outlined above and understanding the fundamental principles of electron configuration and magnetic properties, you can accurately determine whether any given atom is diamagnetic or paramagnetic. Remember to always carefully apply the Aufbau principle, Hund's rule, and the Pauli exclusion principle to accurately determine the electron configuration, which is the key to understanding the magnetic behavior of an atom.