Noble gases rarely ever react with other elements. which rule below explains why?
octet rule
hund's rule
aufbau principle
pauli exclusion principle

Octet Rule

Explanation:

The octet rule talks about the tendency of atom to attain 8 electron in it outer shell. When an atom have fewer outer electrons than 8 they tend to easily react to form stable compounds. The atom that has it outer shell fully filled up are usually very stable and hardly go into a reaction. The octet rule is mostly involved with the s and p orbitals.

Noble gases like Neon and Argon have fully filled outer shell. The valency electron is 8. This fully filled valency shell is responsible for the stable nature of these noble gases. These noble gases find it hard to react with other elements. Example includes Neon and Argon which have atomic numbers of 10 and 18 respectively. The electronic configuration can be represented as follows:

Neon →  2 8

Argon → 2 8 8

Question 1, answer is D because in liquid particles move faster than in solid. The closer the particles, the slower they move, the lesser the energy.

Question 2, answer is A because in liquid, the particles are further away than in solid