Uranium 238, a common isotope of natural uranium (u), decays to form an isotope of thorium (th) which has an atomic mass of 234 amu and 90 protons. how many fewer protons are found in each nucleus of thorium 234 than are found in each nucleus of uranium 238?

2 protons.

Explanation:

1) The number of protons is indicated by the atomic number (Z)

2) Atomic number of uranium-238 and any uranium isotope is the same: 92. You find it in a periodic table.

So, the number of protons of uranium-238 is 92.

3) Atomic number of thorium-234 (and any thorium isotope) is 90, that is why it is told that it has 90 protons.

4) Therefore, the difference on the number of protons in each nucleus of uranium-238 and thorium-234 is 92 - 90 = 2.

double the distance = divide strength by 4