Hund’s Rule: According to this rule “First, one electron is filled in all the sub-orbitals of any orbital and after that pairing starts, that is, pairing is made later, first one electron is filled in all the sub-orbitals.Quantum physics is arguably the greatest intellectual triumph in the history of human civilization, but to most people it seems like it's too remote and abstract to matter. and the particles which do not obey this principle are called bosons, such as photons, gluons, gauge bosons.Ģ. (iii) The particles which follow this principle are called fermions, such as electrons, atoms, neutrons etc. are in the same state or share similar properties) can stay in the same place at the same time. (ii) According to this principle, no two particles (whose spin, colour charge, angular momentum, etc.
For electrons in the same atom, this law states that “no two electrons can have the same four (ie all) quantum numbers”. (i) No two identical fermions can be in the same quantum state at the same time. (Exclusion means to leave, apply a different rule, etc.) According to this principle: Pauli’s Exclusion Principle: This is a theory of quantum mechanics that was propounded by Wolfgang Pauli in 1925. The accuracy with which they can predict the position and energy of electrons is governed by the following principles:ġ. There are some restrictions and limitations to quantum numbers. For the wave motion of electrons in a three-dimensional space around the nucleus, he put forward the wave equation known as Schrodinger’s wave equation, Quantum mechanics. Quantum mechanics was developed by Erwin Schrodinger in \(1926,\) keeping account of wave nature associated with particles like electrons. Quantum numbers distinguish different orbitals based on size, shape, and orientation in space.Īfter the failure of Bohr’s model of the atom due to its inability of explaining Heisenberg’s uncertainty principle and dual nature of particles and the failure of classical physics for microscopic particles, there was a need for a new branch of science to be introduced called “Quantum Mechanics”. Quantum number may be defined as a set of four numbers with the help of which we can get complete information about all the electrons in an atom, i.e., location, energy, the type of occupied, shape, and orientation of the orbital, etc. The spin quantum number on the other side shows the spin or rotation of the electron along its axis only and does not denote any characteristic of the orbital.
The different characteristics of orbitals are represented primarily by the principal quantum number, Azimuthal quantum number, and magnetic quantum number, and these numbers are derived from Schrodinger’s wave equations. Azimuthal Quantum Number or Angular Momentum or Subsidiary (l) Quantum NumberĪtoms have many orbitals around the nucleus differing in their shape, size, and orientation in space.