10.This process of building up the atoms by adding one proton to the nucleus and one electron to the electron cloud is known as the __ a Hund's rule b Pauli exclusion principle c Aufbau principle d None of the above

The correct answer is c) Aufbau principle.<br /><br />The Aufbau principle describes the process of building up atoms by adding one proton to the nucleus and one electron to the electron cloud. It states that electrons fill the lowest energy orbitals first, and then move to higher energy orbitals as the lower ones become filled. This principle helps to explain the arrangement of electrons in the periodic table and the chemical properties of elements.