How to Determine Whether Chlorine Dioxide (ClO2) is Paramagnetic or Diamagnetic

To determine whether the compound chlorine dioxide (ClO2) is paramagnetic or diamagnetic, you can follow these detailed steps:

Understanding the Definitions

Paramagnetic: A substance is considered paramagnetic if it has unpaired electrons which can align with a magnetic field, causing the substance to be attracted to the field.

Diamagnetic: A substance is diamagnetic if all its electrons are paired, resulting in no net magnetic moment, causing it to be slightly repelled by a magnetic field.

Determining the Electron Configuration

The key to understanding the paramagnetic or diamagnetic nature of ClO2 lies in analyzing its electronic structure. Let's break down the steps:

Chlorine (Cl) and Oxygen (O) Electrons

- Chlorine (Cl): Chlorine has an atomic number of 17, with an electron configuration of [Ne] 3s2 3p5.

- Oxygen (O): Oxygen has an atomic number of 8, with an electron configuration of [He] 2s2 2p4.

Calculating the Total Valence Electrons

To find the total valence electrons in ClO2, we need to consider the contributions from each atom:

Chlorine (Cl) contributes 7 valence electrons (5 from 3p and 2 from 3s). Each Oxygen (O) contributes 6 valence electrons (4 from 2p and 2 from 2s).

For ClO2:

Total valence electrons 7 (from Cl) 2 6 (from 2 Oxygen atoms) 19 electrons.

Lewis Structure and Molecular Orbital Theory

The next step involves drawing the Lewis structure for ClO2 and applying molecular orbital theory. Chlorine typically forms two bonds with oxygen atoms, and may have a lone pair:

Draw the Lewis structure for ClO2:The most common resonance structures show that ClO2 has a central chlorine atom bonded to two oxygen atoms with one double bond and one single bond or vice versa, depending on the resonance.

Checking for Unpaired Electrons

After considering the bonding and lone pairs, you will find that there is one unpaired electron in the molecular orbitals of ClO2. This can be determined through careful analysis of the resonance structures.

Conclusion

Since ClO2 has unpaired electrons, it is paramagnetic. This property is crucial in understanding the behavior of ClO2 in the presence of a magnetic field.

Summary

Chlorine dioxide (ClO2) is paramagnetic due to the presence of unpaired electrons in its molecular structure. This knowledge supports the use of the paramagnetic and diamagnetic classification, where compounds containing at least one unpaired electron are paramagnetic, and compounds with all paired electrons are diamagnetic.

To ensure accuracy in identifying paramagnetic and diamagnetic compounds, the spin-only formula can be used. This formula takes into account the number of unpaired electrons in the molecule. If the spin-only formula yields a non-zero number, the molecule is paramagnetic. If it yields a zero, the molecule is diamagnetic.

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