Explain why the nucleus of an atom has a positive electrical charge.

Nucleus of an atom is heavy and positively charged because nucleus is only made up of protons and neutrons.

if two electrons have the same n, the same ℓ, and the same ml, then they are in the same orbital. the pauli exclusion principle states that no two identical fermions (a fancy word for electrons and other subatomic particles like electrons) may occupy the same quantum state in an atom simultaneously.

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.