State the three rules that define how electrons are arranged in atoms

The three correct rules or principles are the Aufbau Principle, Hund’s Rule, and the Pauli Exclusion Principle. Aufbau’s Principle states that each electron orbits the lowest energy orbital. It also states that all orbitals related to an energy level are of equal energy. Hund’s Rule states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals. And finally, the Pauli Exclusion Principle states that a maximum of two electrons may occupy a single orbital, but only if the electrons have opposite spins. Hope this helps.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.