Define A Paramagnetic Substance (Element) And How Can We Predict From Its Electron Configuration?
The correct answer and explanation is :
Definition of a Paramagnetic Substance:
A paramagnetic substance is a material that is attracted to an external magnetic field due to the presence of unpaired electrons in its atomic or molecular electron configuration. These unpaired electrons have magnetic moments that align with the external field, causing the attraction.
How to Predict Paramagnetism from Electron Configuration:
To determine if an element is paramagnetic:
- Write its electron configuration (considering its ground state).
- Identify any unpaired electrons in the atomic orbitals.
- If one or more electrons are unpaired, the element is paramagnetic.
- If all electrons are paired, it is diamagnetic (repelled by a magnetic field).
Explanation (300 Words):
Paramagnetism is a form of magnetism observed in materials that have at least one unpaired electron in their atomic or molecular orbitals. When placed in an external magnetic field, the magnetic moments of the unpaired electrons tend to align with the field, causing the material to be weakly attracted. This behavior is distinct from diamagnetic substances, which have all electrons paired and are weakly repelled by a magnetic field.
The electron configuration of an atom provides a clear way to predict paramagnetism. By applying the Aufbau principle, Pauli exclusion principle, and Hund’s rule, we can systematically fill the atomic orbitals with electrons. If the final configuration shows any orbital (especially in the s, p, d, or f subshells) with a single, unpaired electron, then the atom is paramagnetic.
For example, consider oxygen (O) with atomic number 8. Its electron configuration is:
1s² 2s² 2p⁴The 2p subshell holds four electrons: two will pair in one orbital, and the other two will occupy separate orbitals singly, leading to two unpaired electrons. Hence, oxygen is paramagnetic.
In contrast, neon (Ne) with electron configuration 1s² 2s² 2p⁶ has no unpaired electrons, so it is diamagnetic.
Transition metals often exhibit paramagnetism due to unpaired d-electrons. For instance, Fe (iron) with configuration [Ar] 3d⁶ 4s² has four unpaired d-electrons, making it strongly paramagnetic.
Thus, checking for unpaired electrons in the electron configuration is a reliable method to predict paramagnetic behavior.