Which Of The Following Atoms Is Paramagnetic

Which of the Following Atoms is Paramagnetic? A Deep Dive into Electron Configuration and Magnetism

Determining whether an atom is paramagnetic or diamagnetic hinges on understanding its electron configuration and the behavior of unpaired electrons. This article will explore the fundamental principles of magnetism, delve into the electron configurations of various atoms, and provide a step-by-step method for identifying paramagnetic species. We'll also touch upon the practical applications of understanding paramagnetism.

Understanding Paramagnetism and Diamagnetism

All matter interacts with a magnetic field, but the strength and type of interaction vary greatly. This interaction is determined by the arrangement of electrons within the atom. Two key types of magnetism are:

Diamagnetism

Diamagnetism is a fundamental property of all matter. It arises from the orbital motion of electrons. When an external magnetic field is applied, a small induced magnetic field is generated in the opposite direction, resulting in a weak repulsion from the magnetic field. Diamagnetic materials are weakly repelled by a magnetic field. Importantly, diamagnetism is always present, even in paramagnetic substances. However, it is usually overshadowed by the stronger paramagnetic or ferromagnetic effects.

Paramagnetism

Paramagnetism occurs when an atom possesses unpaired electrons. These unpaired electrons have a net magnetic moment, meaning they act like tiny magnets. When an external magnetic field is applied, these unpaired electrons align themselves with the field, resulting in a net attraction. Paramagnetic materials are weakly attracted to a magnetic field. The strength of paramagnetism is directly proportional to the number of unpaired electrons.

Ferromagnetism

A stronger form of magnetism, ferromagnetism, is exhibited by materials containing unpaired electrons that interact strongly with each other. This strong interaction leads to a spontaneous alignment of the electron spins even in the absence of an external magnetic field. This is responsible for the strong attraction to magnetic fields seen in ferromagnetic materials like iron, nickel, and cobalt. We won't focus on ferromagnetism in this article as it's a more complex phenomenon.

Determining Paramagnetism Using Electron Configuration

The key to determining whether an atom is paramagnetic lies in its electron configuration. To ascertain paramagnetism, follow these steps:

1. Determine the Atomic Number: The atomic number of an element represents the number of protons and, in a neutral atom, the number of electrons.

2. Write the Electron Configuration: Use the Aufbau principle, Hund's rule, and the Pauli exclusion principle to write the electron configuration of the atom. Remember:

   • Aufbau Principle: Electrons fill orbitals in order of increasing energy levels.
   • Hund's Rule: Electrons fill orbitals individually before pairing up within the same subshell.
   • Pauli Exclusion Principle: No two electrons in an atom can have the same set of four quantum numbers (n, l, ml, and ms). This means each orbital can hold a maximum of two electrons with opposite spins.

3. Identify Unpaired Electrons: Once you have the electron configuration, examine each subshell. If a subshell has unpaired electrons (meaning orbitals are singly occupied), the atom is paramagnetic. If all electrons are paired (each orbital is doubly occupied), the atom is diamagnetic.

Examples: Identifying Paramagnetic Atoms

Let's work through some examples to illustrate the process.

Example 1: Oxygen (O)

• Atomic Number: 8
• Electron Configuration: 1s² 2s² 2p⁴
• Analysis: The 2p subshell has four electrons. According to Hund's rule, these electrons will occupy three 2p orbitals, with two orbitals singly occupied and one doubly occupied. Therefore, oxygen has two unpaired electrons and is paramagnetic.

Example 2: Boron (B)

• Atomic Number: 5
• Electron Configuration: 1s² 2s² 2p¹
• Analysis: The 2p subshell has only one electron, which is unpaired. Therefore, boron has one unpaired electron and is paramagnetic.

Example 3: Neon (Ne)

• Atomic Number: 10
• Electron Configuration: 1s² 2s² 2p⁶
• Analysis: All subshells are completely filled, meaning all electrons are paired. Therefore, neon has zero unpaired electrons and is diamagnetic.

Example 4: Nitrogen (N)

• Atomic Number: 7
• Electron Configuration: 1s² 2s² 2p³
• Analysis: The 2p subshell has three electrons, each occupying a separate 2p orbital. Therefore, nitrogen has three unpaired electrons and is paramagnetic.

Example 5: Magnesium (Mg)

• Atomic Number: 12
• Electron Configuration: 1s² 2s² 2p⁶ 3s²
• Analysis: All electrons are paired. Magnesium is diamagnetic.

Example 6: Iron (Fe)

• Atomic Number: 26
• Electron Configuration: [Ar] 3d⁶ 4s²
• Analysis: The 3d subshell has six electrons, meaning four electrons are unpaired. Therefore, iron has four unpaired electrons and is paramagnetic. This example demonstrates that even atoms with many electrons can still exhibit paramagnetism due to unpaired electrons in the d orbitals.

Example 7: Copper (Cu)

• Atomic Number: 29
• Electron Configuration: [Ar] 3d¹⁰ 4s¹ (Note: this is an exception to Hund's rule due to stability)
• Analysis: Although copper has many electrons, its configuration shows one unpaired electron in the 4s orbital. Therefore, copper is paramagnetic.

Practical Applications of Understanding Paramagnetism

The paramagnetic properties of certain atoms and molecules find applications in various fields:

• Medical Imaging (MRI): Magnetic Resonance Imaging (MRI) relies on the paramagnetic properties of hydrogen atoms in water molecules within the body. The alignment and relaxation of these atoms in a strong magnetic field provide detailed images of internal organs and tissues.

• Oxygen Sensors: The paramagnetism of oxygen is used in oxygen sensors to measure oxygen levels in various environments, including medical applications and industrial processes.

• Chemical Analysis: Paramagnetism is a useful tool in chemical analysis to determine the presence and concentration of paramagnetic species in samples.

• Materials Science: Understanding paramagnetism is crucial in the development of new materials with specific magnetic properties, utilized in electronic devices and energy technologies.

Conclusion

Determining whether an atom is paramagnetic or diamagnetic is a straightforward process that requires understanding electron configurations. By following the steps outlined in this article, identifying paramagnetic species becomes a simple matter of counting unpaired electrons. The ability to differentiate between these magnetic properties is critical in numerous scientific and technological applications, highlighting the importance of this fundamental concept in chemistry and physics. Remember to always use the Aufbau principle, Hund's rule, and the Pauli exclusion principle to correctly determine the electron configuration and, consequently, the magnetic properties of any atom. This understanding forms a foundation for more advanced studies in magnetism and materials science.