according to him each electron has an exclusive set of quantum numbers and no two electrons can have the same combination of four quantum numbers

describes the size of the orbital the electron residing

describes the shape of an orbital

defines the orientation of the orbital in space and the electron

defines the direction that the electron spins on its own axis

the arrangement of electrons within the orbitals of an atom to know more about an atoms electronic property.

according to this principle the electrons in an atom fill up its atomic orbitals.

aufbau in german means

this rule stated that before additional electrons with opposite spins can occupy the same orbitals, single electrons with the same spin must occupy each equal-energy orbital first.

atoms with unpaired electrons in their electron configuration and are affected by a magnetic fields are called

atoms with no unpaired electrons in their electron configuration are called diamagnetic.