Question

In an atom two electrons can pair up and occupy an energy level, but their spins are __________ to each other, canceling their magnetic field.​

Answer 1

In an atom two electrons can pair up and occupy an energy level, but their spins are opposite to each other, canceling their magnetic field.​

• According to Pauli's Principle, no two electrons can have all the identical values of all the four quantum numbers, i.e. no more than two electrons can occupy same orbital and the electrons in the same orbital must have opposite spins.
• The spins of the electrons produces a magnetic field, and if these spins are opposite in nature then they cancel out each other thereby cancelling the magnetic field.