Hund’s Rule

Pairing of electrons in orbitals of same subshell cannot take place until all orbitals have one electron

Aufbau Rule

Orbitals are filled with electrons in the increasing order of energy

Quantum Numbers

Set of four numbers to represent size, shape, orientation and energy of orbits and spin of the electron

Orbitals

Regions around the nucleus where the probability of finding electrons are maximum

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