One of the daughter elements of uranium-238 is thorium-234 (Th-234).

Here's why:

* Uranium-238 (U-238) undergoes alpha decay, meaning it emits an alpha particle (consisting of 2 protons and 2 neutrons).

* When U-238 decays, it loses 4 atomic mass units (the alpha particle) and 2 protons, transforming into Th-234.

This is just the beginning of a long decay chain for U-238, which eventually leads to the stable isotope lead-206 (Pb-206).