Quantum Number
To describe the location of an electron inside an atom we need a set of 4 numbers known as Quantum Numbers. These Quantum Number helps in distinguishing different orbitals which contain electron. Orbitals that have a smaller number mean they are closer to the nucleus, have a smaller size, and have a larger probability of finding an electron. The four types of Quantum Numbers are listed below:
- Principal Quantum Number
- Azimuthal Quantum Number
- Magnetic Quantum Number
- Spin Quantum Number
Principal Quantum Number(n)
It is represented by ‘n’. It gives the idea of a shell in which an electron is present and also about its energy. A lower value of ‘n’ means the shell is closer to the nucleus and has lower energy. It is given by n = 1,2,3…
n | Shell |
---|---|
1 | K |
2 | L |
3 | M |
4 | N |
Azimuthal Quantum Number(l)
It is represented by ‘l’. It gives an idea of the subshell and 3D shape of the orbital. The subshells are given as s, p, d, and f. The value assigned to subshells are 0 = s, 1 = p, 2 = d, 3 = f. A shell contains 0 to n-1 subshell. For Example, the third shell i.e. n = 3 will have 0 to (3-1) subshells i.e. 0 to 2 subshells which include 0,1 and 2.
n | l | Subshell Notation |
---|---|---|
1 | 0 | 1s |
2 | 0 | 2s |
2 | 1 | 2p |
3 | 0 | 3s |
3 | 1 | 3p |
3 | 2 | 3d |
Magnetic Quantum Number(ml)
It is represented by ml. It gives an idea of the orientation of orbital in space with respect to coordinate axes. A subshell contains -l to l orbitals. For Example, subshell p contains -1 to 1 orbital i.e. -1, 0, 1, a total of three orbitals oriented along different coordinate axes and coordinate planes.
Spin Quantum Number(ms)
It is represented by ms. It gives an idea about the spinning or orientation of electrons. It takes the value of +1/2 or -1/2. If ms is +1/2 it means the electron is rotating clockwise and is represented as ⇡ while if ms is -1/2 it means the electron is rotating anticlockwise and is represented as ⇣.
As of now, we have learned all the atomic models, now we will look at the properties of all the subatomic particles.
Atomic Structure
Atomic structure is the structure of an atom that consists of a nucleus at the center containing neutrons and protons, while electrons revolve around the nucleus. Atoms are made up of a very tiny, positively charged nucleus that is surrounded by a cloud of negatively charged electrons.
The earliest concept of atoms was given by Indian philosopher Maharshi Kanad who proposed that matter is made up of microscopic indestructible particles called ‘Parmanu’. A Greek philosopher named Democritus also initially claimed that matter is formed of atoms, and is credited with developing the concepts of atomic structure and quantum mechanics. Later in the 1800s, John Dalton a British Scientist put out the first atomic structure scientific theory.
This article explores the concept of atomic structure in detail, including the atomic models, and the concept of quantum theory.
Table of Content
- What is Atomic Structure?
- Atomic Models
- Dalton’s Atomic Theory
- Postulates of Dalton’s Atomic Theory
- Demerits of Dalton’s Atomic Theory
- Thomson’s Atomic Model
- Cathode Ray Experiment
- Observations of Cathode Ray Experiment
- Discovery of Electron
- Plum Pudding Model
- Drawbacks of Thomson’s Atomic Model
- Rutherford Atomic Model
- Alpha Ray Scattering Experiment
- Observation of Alpha Ray Scattering Experiment
- Conclusion of Rutherford’s model
- Discovery of Nucleus
- Limitations of Rutherford Atomic Model
- Bohr’s Atomic Model
- Postulates of Bohr’s Atomic Theory
- Limitations of Bohr’s Atomic Theory
- Quantum Mechanical Model of Atom
- Dual Behaviour of Matter
- Heisenberg Uncertainty Principle
- Schrodinger Wave Equation
- Postulates of Quantum Mechanical Model of Atom
- Quantum Number
- Principal Quantum Number(n)
- Azimuthal Quantum Number(l)
- Magnetic Quantum Number(ml)
- Spin Quantum Number(ms)
- Subatomic Particles
- Isotopes
- Atomic Structure of Isotopes
- Electronic Configuration of Elements
- Aufbau Principle
- Hund’s Rule
- Pauli Exclusion Principle
- Atomic Structure Class 11