Dobereiner's Triads or the law of triads divides elements showing similar properties into groups of three.

The Hund rule of maximum multiplicity states the electrons fills the degenerate orbitals singly before getting paired.

Robert Boyle was a chemist of the 17th century and a founder of the modern chemistry.

Pauli Exclusion Principle: An orbital cannot take more than two electrons.

The aufbau principle provides a helpful rule in the ordering of atomic orbitals.

The energy of the atomic orbital is decided by the size and shape of the orbital

Atomic orbitals are building blocks of the modern quantum mechanics model.

Spin quantum number decides the orientation of the intrinsic angular momentum.

Magnetic quantum number, m_l = … −2, −1, 0, 1, 2…

Azimuthal Quantum Number, l = 0, 1, 2, 3…