Paramagnetism and Diamagnetism: Videos & Practice Problems

An orbital can hold a maximum of 2 electrons with opposite spins, as stated by the Pauli exclusion principle. Substances are classified as paramagnetic if they have at least one unpaired electron, making them responsive to magnetic fields, while diamagnetic substances have all electrons paired. Understanding these concepts is crucial for determining electron configurations in elements and ions, where paramagnetic elements possess unpaired electrons, and diamagnetic elements have paired electrons in all orbitals.

Paramagnetism and Diamagnetism

In atomic theory, understanding the behavior of electrons in orbitals is crucial, particularly when discussing the concepts of paramagnetism and diamagnetism. Each orbital can accommodate a maximum of two electrons, which must have opposite spins, as dictated by the Pauli exclusion principle. This principle is fundamental in determining the magnetic properties of substances.

Paramagnetic materials contain at least one unpaired electron in their orbitals, making them responsive to external magnetic fields. For instance, if we examine an s orbital where all electrons are paired, it does not contribute to paramagnetism. However, in p orbitals, if there is an unpaired electron, the substance is classified as paramagnetic. The presence of even a single unpaired electron is sufficient for a substance to exhibit magnetic properties.

In contrast, diamagnetic substances have all their electrons paired within their orbitals. This means that in both s and p orbitals, every electron is paired with another, resulting in no unpaired electrons. Consequently, diamagnetic materials are not influenced by magnetic fields, as they lack the necessary unpaired electrons to exhibit magnetic behavior.

When determining the electron configurations of elements or ions, it is essential to identify whether they are paramagnetic or diamagnetic. A paramagnetic element or ion will have at least one unpaired electron, while a diamagnetic one will have all electrons paired. This distinction is vital for predicting the magnetic properties of various substances.

Paramagnetism and Diamagnetism Example

To determine whether a vanadium atom is paramagnetic or diamagnetic, we first recognize that a neutral vanadium atom is represented by the symbol V and has an atomic number of 23. The electron configuration for vanadium can be expressed as [Ar] 4s2 3d3. This configuration indicates that the 4s orbital is fully occupied with 2 electrons, while the 3d sublevel contains 3 electrons.

In atomic orbitals, the s orbital consists of a single orbital that can hold a maximum of 2 electrons, while the d sublevel comprises 5 orbitals, each capable of holding 2 electrons, for a total of 10 electrons. In the case of vanadium, since the 4s orbital is filled and the 3d sublevel has 3 electrons, we can analyze the distribution of these electrons. The 3d electrons can be arranged in such a way that there are unpaired electrons present.

Specifically, since there are 3 electrons in the 3d orbitals, they will occupy separate orbitals before pairing occurs, leading to one unpaired electron. The presence of at least one unpaired electron indicates that the vanadium atom is paramagnetic. In summary, a paramagnetic species is characterized by having unpaired electrons, while a diamagnetic species has all electrons paired. Therefore, vanadium, with its unpaired electron, is classified as paramagnetic.

Which of the following atoms has the most unpaired electrons? 

• A. Co
• B. Mn
• C. Ti
• D. Zn
• E. Fe

Answer: (B)

Write the condensed electron configuration for the nickel (III) ion and state if it is paramagnetic or diamagnetic.

• A. [Ar]3d⁷; Paramagnetic
• B. [Ar]3d⁷; Diamagnetic
• C. [Ar]4s²3d⁵; Paramagnetic
• D. [Ar]4s²3d⁵; Diamagnetic

Answer: (A)

Write the condensed electron configuration for the copper (I) ion and is it magnetic?

• A. $\left[ Ar\right]4s^23d^9$ ; Diamagnetic
• B. $\left[Ar\right]3d^{10}$ ; Diamagnetic
• C. $\left[ Ar\right]4s^23d^9$ ; Paramagnetic
• D. $\left[ Ar\right]3d^{10}$ ; Paramagnetic

Answer: (B)

Here’s what students ask on this topic:

What is the difference between paramagnetic and diamagnetic substances?

Paramagnetic substances have at least one unpaired electron in an orbital, making them influenced by magnetic fields. Diamagnetic substances, on the other hand, have all their electrons paired within their orbitals and are not influenced by magnetic fields. This difference arises from the electron configurations of the elements or ions. In paramagnetic substances, the presence of unpaired electrons creates a net magnetic moment, while in diamagnetic substances, the paired electrons cancel out each other's magnetic moments.

How can you determine if an element is paramagnetic or diamagnetic?

To determine if an element is paramagnetic or diamagnetic, you need to examine its electron configuration. If the electron configuration shows at least one unpaired electron in any of the orbitals, the element is paramagnetic. If all the electrons are paired in their respective orbitals, the element is diamagnetic. For example, the electron configuration of oxygen (O) is 1s² 2s² 2p⁴, which has two unpaired electrons in the 2p orbitals, making it paramagnetic. In contrast, the electron configuration of neon (Ne) is 1s² 2s² 2p⁶, with all electrons paired, making it diamagnetic.

Why are paramagnetic substances attracted to magnetic fields?

Paramagnetic substances are attracted to magnetic fields because they have unpaired electrons in their orbitals. These unpaired electrons have magnetic moments that align with the external magnetic field, creating a net magnetic moment that causes the substance to be attracted to the field. The alignment of the magnetic moments with the external field results in a force that pulls the paramagnetic substance towards the source of the magnetic field.

What role does the Pauli exclusion principle play in determining paramagnetism and diamagnetism?

The Pauli exclusion principle states that an orbital can hold a maximum of two electrons with opposite spins. This principle is crucial in determining paramagnetism and diamagnetism because it dictates the electron configurations of elements and ions. In paramagnetic substances, the presence of unpaired electrons in orbitals results from the Pauli exclusion principle, as not all electrons can pair up. In diamagnetic substances, all electrons are paired within their orbitals, adhering to the Pauli exclusion principle, which ensures that each orbital has two electrons with opposite spins.

Can an ion be paramagnetic or diamagnetic? How?

Yes, an ion can be paramagnetic or diamagnetic, depending on its electron configuration. When an atom loses or gains electrons to form an ion, its electron configuration changes, which can result in unpaired or paired electrons. If the ion has at least one unpaired electron in its orbitals, it is paramagnetic. If all the electrons in the ion's orbitals are paired, it is diamagnetic. For example, the Fe²⁺ ion has the electron configuration [Ar] 3d⁶, with four unpaired electrons, making it paramagnetic. In contrast, the Zn²⁺ ion has the electron configuration [Ar] 3d¹⁰, with all electrons paired, making it diamagnetic.