1. Hydrogen (H): Makes up about 70.6% of the Sun's mass.
2. Helium (He): Makes up about 27.4% of the Sun's mass.
3. Oxygen (O): Makes up about 0.8% of the Sun's mass.
4. Carbon (C): Makes up about 0.3% of the Sun's mass.
5. Neon (Ne): Makes up about 0.2% of the Sun's mass.
These elements are fused together in the Sun's core, creating the energy that powers the star.