1.9 Predict and explain the changes in the potential energy, the kinetic energy and the total energy as two isolated helium (or another noble gas) atoms approach each other.

What happens to potential, kinetic, and total energy when two noble gas atoms are far apart?

• Potential Energy: High (weak attraction)

• Kinetic Energy: Constant (atoms move freely)

• Total Energy: Constant (sum of PE + KE)

What happens to the energy when two noble gas atoms start moving closer together?

• Potential Energy: Decreases (weak van der Waals forces attract them)

• Kinetic Energy: Increases slightly (atoms speed up due to attraction)

• Total Energy: Constant (energy is conserved)

What happens to energy when two noble gas atoms reach their most stable distance?

• Potential Energy: At its lowest (system is most stable)

• Kinetic Energy: At its highest within this range (atoms vibrate slightly)

• Total Energy: Constant (sum of PE + KE remains the same)

What happens when two noble gas atoms get too close together?

• Potential Energy: Increases rapidly (electron clouds repel each other)

• Kinetic Energy: Decreases slightly (atoms slow down due to repulsion)

• Total Energy: Constant (energy is conserved)