Which Of The Following Atoms Is Diamagnetic In Its Ground-state

Which ofthe following atoms is diamagnetic in its ground‑state? The answer is neon, a noble gas whose completely filled electron shells leave no unpaired electrons, resulting in diamagnetic behavior. This article explains the underlying principles, walks through the electron configurations of typical candidates, and clarifies why neon (and a few other atoms) exhibit diamagnetism while most others do not.

Introduction

Understanding magnetism at the atomic level requires examining how electrons occupy energy levels and whether any of them remain unpaired. When all electrons are paired, their magnetic moments cancel out, and the atom displays diamagnetism—a weak repulsion from an external magnetic field. Conversely, any unpaired electron introduces a net magnetic moment, giving the atom paramagnetism. The question “which of the following atoms is diamagnetic in its ground‑state” therefore hinges on identifying the species whose electron configuration yields only paired electrons.

Understanding Magnetic Properties of Atoms

The Origin of Atomic Magnetism

• Paramagnetism arises from unpaired electrons whose spins align partially with an external magnetic field, producing a measurable attraction.
• Diamagnetism is a universal weak effect caused by the induction of opposing magnetic moments in paired electrons; it is most evident when no unpaired electrons exist.

How to Predict Magnetic Behavior

1. Write the ground‑state electron configuration of the atom.
2. Count the electrons in each subshell (s, p, d, f). 3. Determine pairing: if every subshell contains an even number of electrons, the atom is diamagnetic; otherwise, it is paramagnetic.

Electron Configurations of Common Atoms

Below is a quick reference for several frequently tested atoms, highlighting the presence or absence of unpaired electrons.

From the table, He, Be, Ne, and Mg are the atoms that are diamagnetic in their ground state. In many multiple‑choice settings, the only noble‑gas option presented is neon, making it the correct answer.

Detailed Example: Why Neon Is Diamagnetic

Neon (atomic number 10) possesses the electron configuration 1s² 2s² 2p⁶. Each subshell is fully occupied:

• 1s holds 2 electrons (paired).
• 2s holds 2 electrons (paired). * 2p holds 6 electrons, filling all three p orbitals with two electrons each (paired).

Because every electron has a partner with opposite spin, the net magnetic moment is zero. When an external magnetic field is applied, the induced currents in the electron clouds generate a tiny magnetic field that opposes the applied field—this is the hallmark of diamagnetism.

Why the Other Options Fail

• Oxygen (1s² 2s² 2p⁴) has two unpaired electrons in separate p orbitals, giving it a net magnetic moment and rendering it paramagnetic.
• Nitrogen (1s² 2s² 2p³) contains three

unpaired electrons, resulting in a paramagnetic nature.

Conclusion

Understanding magnetic behavior hinges on electron configuration and the presence of unpaired electrons. Diamagnetism, a universal property arising from paired electrons inducing opposing magnetic moments, is observed in atoms like He, Be, Ne, and Mg where all subshells are fully occupied. Paramagnetism, characterized by attraction to magnetic fields, occurs whenever unpaired electrons exist, as seen in elements such as H, Li, B, C, N, O, F, and Na. By systematically analyzing an atom's ground-state electron configuration—identifying filled subshells and paired electrons—its magnetic properties can be reliably predicted. Neon, with its complete 1s²2s²2p⁶ configuration, serves as a quintessential example of diamagnetism, demonstrating how the absence of unpaired electrons results in a net zero magnetic moment and weak repulsion from magnetic fields. This fundamental distinction underpins the classification and prediction of magnetic behavior across the periodic table.