Unpaired Electrons: Reif's Thermo Book Explained

• quasar987
In summary, Reif's thermo book discusses the possibility of having more than one unpaired electron in a substance with n magnetic atoms per unit volume placed in an external magnetic field B. However, Hund's rules state that an atom can have more than one unpaired electron in different angular momentum states. This is demonstrated through the electron configurations of various atoms, such as Carbon having 2 unpaired electrons in different orbital states.
quasar987
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In Reif's thermo book, one can read

"Consider a substance which contains n magnetics atoms per unit volumes and which is placed in an external magnetic hield B. Assume that each atom has spin 1/2 (corresponding to one unpaired electron) and an intrinsic magnetic moment of $\mu$."

He makes it sound like it's possible to have more than one unpaired electron. Is this so? I interpret "unpaired" as "there is one electron in a state r and spin up (resp. down) such that there are no electrons in state r with spin down (resp. up). But as soon as you add one more electrons, it will get in state r with spin down (resp. up) so there are no more unpaired electrons. Hence it's impossible to have more than 1 unpaired. Is this how it work?

I'm not sure if I understand you completely but... look up Hund's rules. An atom can have more than one unpaired electron. They're in different angular momentum states though.

Surely if you've ever studied chemistry you might know that "unpaired electrons" occur when writing the electron configurations for various atoms. For instance, the Carbon atom has 2 unpaired electrons, N has 3, etc.

Daniel.

What is an unpaired electron then?

I've said what I remember from chemistry. You fill up the states two by two since an up and a down can occupy the same state. If there is an even number of electrons, there there is no unpaired electrons; if the number is odd there is one.

Nope, Hund rules make it that the Carbon atom which had 6 electrons altogether have the configuration

1s2 2s2 2p2

, but the 2 electrons in the "p" orbital are uncoupled (i.e. in different total angular momentul states), meaning that the spins are not antiparallel in the same orbital (p_{x}), but are alligned & parallel in the 2 orbitals:2p_{x} & 2p_{y}, rendering the total spin 1, instead of 0.

Daniel.

Ah, I see, thank you.

What are unpaired electrons?

Unpaired electrons are electrons that exist in an atom's outermost energy level and are not paired with another electron. They are highly reactive and play a crucial role in chemical bonding and the properties of materials.

How are unpaired electrons related to Reif's Thermo Book?

Reif's Thermo Book is a textbook that explains the principles of thermodynamics, including the concept of unpaired electrons and their role in chemical reactions and energy transfer. It provides a comprehensive understanding of how unpaired electrons contribute to the behavior of matter.

What is the significance of unpaired electrons in chemistry?

Unpaired electrons are important in chemistry because they determine the chemical and physical properties of elements and compounds. They are responsible for the formation of chemical bonds, which determine the reactivity and stability of molecules and materials. Unpaired electrons also play a key role in the study of magnetism and electricity.

How are unpaired electrons represented in electron configurations?

Unpaired electrons are represented in electron configurations as arrows pointing up or down in the electron cloud diagram. Each arrow represents one electron, and when there are two arrows pointing in opposite directions in the same energy level, it indicates an unpaired electron.

What are the applications of understanding unpaired electrons?

Understanding unpaired electrons has various applications in fields such as materials science, biochemistry, and pharmaceuticals. It allows for the prediction and control of chemical reactions and properties of materials, which is essential in the development of new technologies and medicines. Additionally, knowledge of unpaired electrons is crucial in the study of environmental processes and the behavior of matter in extreme conditions.

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