If an isotope of uranium, uranium-235, has 92 protons how many protons does the isotope uranium-238 have? Why?
- redbeardthegiantLv 79 years agoFavorite Answer
U238 also has 92 protons.
Any variety of uranium will.
If it had different from 92, it would not be uranium; if it has 92 it is uranium.
mnemonic: isotoPe where the capitalized P means there are the same [iso] number of Protons
- 9 years ago
Atoms are made up of protons, neutrons and electrons. The mass of a proton and neutron can be said to equal 1, whereas the mass an electron contributes to the atom is negligible (effectively 0).
If uranium-235 has 92 protons, it has 143 neutrons to make one atom of U-235.
An isotope of an element is one with the same chemical identity (therefore proton number is equal) but can have a varying mass. Since the proton number is equal, the difference in mass can only arise by a varying number of neutrons.
Therefore Uranium-238 has 92 protons and 146 neutrons, making one atom.