You're asking about the composition of the solar nebula, the cloud of gas and dust that formed our solar system. Here's the breakdown of the major components, from highest to lowest percentage by mass:

1. Hydrogen (H): The most abundant element in the universe, making up about 70% of the solar nebula's mass.

2. Helium (He): The second most abundant element, comprising about 28% of the nebula's mass.

3. All Other Elements: These include heavier elements like oxygen, carbon, nitrogen, iron, silicon, etc., and make up only about 2% of the total mass.

Important Note: While hydrogen and helium are the most abundant by mass, the other elements (even though they represent a small percentage of the overall mass) are crucial for forming planets, moons, and other solid bodies in the solar system.

Let me know if you have any other questions about the solar nebula or the formation of our solar system!