Question

The radioactive isotope 238u decays in a series of nuclear reactions that includes another uranium isotope, 234u, and three lead isotopes, 214pb, 210pb, and 206pb. how many neutrons, protons, and electrons are in each of these five isotopes

Answer 1

The mentioned isotopes are isotopes of elements Uranium (U) and Lead (Pb). The atomic number of U and Pb are 92 and 82, respectively. When an isotope is reported as U-238 for example, 238 is the mass number, which is the sum of the number of protons and neutrons. Since we know the atomic number, we can find the neutrons from the mass number. For the number of electrons, it is equal to the number of protons because it is neutral.

1. U-238
Number of protons: 92
Number of electrons: 92
Number of neutrons: 238 - 92 = 146

2. U-234
Number of protons: 92
Number of electrons: 92
Number of neutrons: 234 - 92 = 142

3. Pb-214
Number of protons: 82
Number of electrons: 82
Number of neutrons: 214 - 82 = 132

4. Pb-210
Number of protons: 82
Number of electrons: 82
Number of neutrons: 210 - 82 = 128

5. Pb-206
Number of protons: 82
Number of electrons: 82
Number of neutrons: 206 - 82 = 124