Quantum Numbers: Deciphering Electronic Configuration in Chemistry
by Yuvi K - December 16, 2023
Significance of Quantum Numbers in Chemistry: Deciphering Electronic Configuration
Understanding the quantum numbers is an essential part of mastering the concepts of chemistry. This is because they are closely related to explaining the electronic configuration of atoms in the periodic table. Quantum numbers are used to solve various puzzles related to atomic structure and assistance in dealing with them is extremely helpful in many branches of learning.
What are Quantum Numbers?
Quantum numbers are mathematical devices used to explain the properties of atoms precisely, owing to their random and unpredictable behaviour. They are represented by symbols which in turn are used to determine the behaviour of the electrons of atoms in a given environment. A quantum number is an integer that describes some property of a particle, such as its location, energy content, direction of motion, or color.
Principle Quantum Number (n):
The principle quantum number, (n), is the most significant number in the quantum number series. It is the quantum number that expresses the energy state of an orbital or electron. (n) determines the size, shape, and capacity of a particular orbital. It has a value between 1 and 7. Larger numbers indicate higher energy, while lower numbers indicate lower energy. As (n) increases, the size of the atomic orbit also increases, and the electrons become less tightly bound to the nucleus.
Azimuthal Quantum Number (ℓ):
The Azimuthal quantum number, (ℓ), represents the shapes of the orbitals. It is also referred to as the orbital quantum number, and is denoted by a letter instead of a number. This letter designates an angular momentum value. It has values from 0 to (n-1). (ℓ) divides the various orbitals in the same electron shell into different shapes—known as s, p, d, and f orbitals.
Magnetic Quantum Number (mℓ):
The Magnetic quantum number, (mℓ), is the number that determines the orientation in space of the orbital that holds a particular electron. This orientation depends upon the Azimuthal quantum number, (ℓ).
(mℓ) has values from –(ℓ) to +(ℓ).
Spin Quantum Number (ms):
The Spin quantum number, (ms), is the fourth quantum number which describes the spin of a particle. The spin quantum number is either -½ or +½, which indicate that the electron is spinning clockwise or counter-clockwise.
Questions Concerning Quantum Numbers:
Now that quantum numbers are discussed, we will delve deeper into questions and apply this knowledge to solve them.
Q.1. What is the electronic configuration of carbon?
The electronic configuration of carbon is 2,4. It has two electrons in its first orbital and four electrons in its second orbital. As the nucleus has 4 protons, its principle quantum number (n) is equal to 2. Its azimuthal quantum number (ℓ) is 0 in the first orbital and 1 in the second. The value of its magnetic quantum number, (mℓ) is ranging from –1 to 1. Its spin quantum number, (ms) is either +½ or -½ for each electron.
Q2. What would be the electronic configuration of Sodium?
The electronic configuration of sodium is 2,8,1. It has two electrons in its first orbital, eight in its second, and one in its third. Sodium has 11 protons, so its principle quantum number (n) is equal to 3. Its azimuthal quantum number (ℓ) is 0 in the first orbital, 1 in the second, and 2 in the third. The value of its magnetic quantum number, (mℓ) would range from–2 to 2 in the third orbital and -1 to 1 in the other two. Its spin quantum number, (ms) would either be +½ or -½ for each electron.
Table Representing Allowing Different Combinations of Quantum Numbers
| Principle Quantum Number (n) | Azimuthal Quantum Number (ℓ) | Magnetic Quantum Number (ml) | Spin Quantum Number (ms) |
|---|---|---|---|
| 1-7 | 0- (n-1) | -ℓ to +(ℓ) | +½ or -½ |
Conclusion
In summary, the significance of quantum numbers in chemistry is tremendous. Their use in understanding electronic configuration within the periodic table is key. They are extremely helpful in solving various puzzles related to atomic structure and they are important in the field of atomic physics. While mastering them can prove to be difficult, it is definitely a rewarding and exciting accomplishment.
> **Note:** (प्रस्थान युग्म संख्या (n): Principle quantum number, अजीमुत्ला युग्म संख्या (ℓ): Azimuthal quantum number, चुंबकीय युग्म संख्या (mℓ): Magnetic quantum number, घुमण्ड युग्म संख्या (ms): Spin quantum number )
