Electronic Structure: Electron Spin: Videos & Practice Problems

According to the Pauli exclusion principle, an orbital can hold a maximum of two electrons with opposite spins. One electron spins clockwise, represented as +1/2, while the other spins counterclockwise, represented as -1/2. This concept is crucial for understanding electron configurations and the behavior of atoms in chemical reactions. The arrangement of electrons in orbitals influences properties such as reactivity and bonding, forming the foundation for concepts like acid-base indicators and enzyme activity in biochemical pathways.

Electronic Structure: Electron Spin Concept 1

Now, an orbital can hold a maximum of 2 electrons that have opposite spins according to the Pauli exclusion principle. It states that no two electrons found within an orbital can have the same electron spin. One has to spin up and one has to spin down. When we talk about this electron spin, it concerns the rotational spin of an electron inside an atomic orbital. We start out filling an orbital with an electron that points up, followed by the next one pointing down. If we were to fill out this orbital, we would use arrows to depict the electrons within it: one would point up and one would point down. They have opposite spins inside the same orbital. Realize here that the electron that points up has an electron spin value of plus one-half. Pointing up, it spins clockwise, and an electron that points down has an electron spin value of minus a half. Pointing down means that it spins counterclockwise. So, just remember, plus a half is synonymous with clockwise, and negative a half is synonymous with counterclockwise in relation to an electron spin.

Electronic Structure: Electron Spin Example 1

Here it says to provide the n value, subshell letter, and electron spin for the highlighted electron in a third principle level. Alright. So here when we're talking about the 3rd principle level, we're talking about the energy level or shell number. So here this means that n equals 3 because, remember, energy level, shell number, principal level, all referring to the n value. That means the answer is either b or d. Next, we have an image here of 3 orbitals. You have to think about which subshell letter has 3 orbitals. Remember, s only has 1, p is the one that has 3, d has 5. Alright. So we're dealing with p. So the subshell letter is p. So far it's still b or d. Now we look at the electron within that particular orbital. Which way is it pointing? Is it pointing up or is it pointing down? We can see that the electron that's highlighted is pointing down. That means its electron spin would be minus a half. So that would mean that option would be our correct answer.

Which of the following can represent the highlighted electron in a set of 5d orbitals.

• A. n = 5, subshell = f, electron spin = –1/2
• B. n = 4, subshell = s, electron spin = –1/2
• C. n = 5, subshell = d, electron spin = +1/2
• D. n = 5, subshell = p, electron spin = –1/2
• E. n = 5, subshell = s, electron spin = +1/2

Answer: (C)

Here’s what students ask on this topic:

What is the Pauli exclusion principle and how does it relate to electron spin?

The Pauli exclusion principle states that no two electrons in the same atom can have identical quantum numbers. This principle is crucial for understanding electron configurations. In terms of electron spin, it means that an orbital can hold a maximum of two electrons, and these electrons must have opposite spins. One electron will have a spin quantum number of +1/2 (clockwise), and the other will have a spin quantum number of -1/2 (counterclockwise). This arrangement minimizes electron repulsion within the orbital and is fundamental to the structure of atoms and their chemical behavior.

How do electron spins affect the chemical properties of an atom?

Electron spins play a significant role in determining the chemical properties of an atom. The arrangement of electrons in orbitals, including their spins, influences how atoms interact with each other. For example, the spin pairing of electrons in orbitals affects the atom's magnetic properties and its ability to form bonds. Unpaired electrons with the same spin can lead to paramagnetism, while paired electrons result in diamagnetism. Additionally, the specific electron configuration, including spin states, determines the atom's reactivity and the types of chemical bonds it can form, impacting molecular structure and stability.

What is the significance of the spin quantum number in electron configuration?

The spin quantum number (s) is crucial in electron configuration as it specifies the intrinsic angular momentum (spin) of an electron within an orbital. It can have values of +1/2 or -1/2, representing clockwise and counterclockwise spins, respectively. This quantum number ensures that electrons within the same orbital have opposite spins, adhering to the Pauli exclusion principle. The spin quantum number helps in predicting the magnetic properties of atoms and molecules, as well as their behavior in external magnetic fields. It also plays a role in determining the overall energy state of the atom.

How do you represent electron spins in orbital diagrams?

In orbital diagrams, electron spins are represented by arrows. An upward arrow (↑) indicates an electron with a spin quantum number of +1/2 (clockwise spin), while a downward arrow (↓) indicates an electron with a spin quantum number of -1/2 (counterclockwise spin). When filling orbitals, the first electron is usually represented with an upward arrow, and if a second electron is added to the same orbital, it is represented with a downward arrow. This notation visually demonstrates the Pauli exclusion principle, showing that the two electrons in the same orbital have opposite spins.

What is the difference between clockwise and counterclockwise electron spin?

Clockwise and counterclockwise electron spins refer to the two possible orientations of an electron's intrinsic angular momentum. A clockwise spin is represented by a spin quantum number of +1/2, while a counterclockwise spin is represented by a spin quantum number of -1/2. These spins are crucial for the Pauli exclusion principle, which states that two electrons in the same orbital must have opposite spins. The difference in spin direction helps minimize electron repulsion within the orbital and is essential for the stability and behavior of atoms in chemical reactions.