* 100 Hydrogen atoms: Hydrogen has an atomic mass of approximately 1 atomic mass unit (amu). So, 100 hydrogen atoms would have a mass of about 100 amu.

* 4 Sulfur atoms: Sulfur has an atomic mass of approximately 32 amu. Therefore, 4 sulfur atoms would have a mass of about 128 amu.

* 1 Lanthanum atom: Lanthanum has an atomic mass of approximately 139 amu.

Conclusion:

* 1 Lanthanum atom has the most mass, followed by 4 Sulfur atoms, and lastly by 100 Hydrogen atoms.