Uranium of atom number 92 and mass number 238 emits an alpha particle from its nucleus. The new nucleus formed has respectively, atomic number and mass numb...

Uranium of atom number 92 and mass number 238 emits an alpha particle from its nucleus. The new nucleus formed has respectively, atomic number and mass number

Answer Details

When Uranium-238 emits an alpha particle from its nucleus, it loses two protons and two neutrons. An alpha particle is a helium nucleus, consisting of two protons and two neutrons. This means that the atomic number of the new nucleus will be two less than the original uranium nucleus, which had an atomic number of 92. So, the new nucleus will have an atomic number of 90. Since the mass number is the total number of protons and neutrons in the nucleus, and we have lost two protons and two neutrons, the mass number of the new nucleus will be 238 - 4 = 234. Therefore, the answer is option D: 90 and 234.