The atomic symbol 206

82 Pb represents lead-206 (Pb-206), an isotope that has 82 protons and 124 neutrons. Which atomic symbol could represent an isotope that undergoes radioactive decay to produce Pb-206?

A. 238

92 U

B. 222

87 Pb

C. 178

72 Hf

D. 192

77 Pb

I think the correct answer from the choices listed above is option A. The atomic symbol that could represent an isotope that undergoes radioactive decay to produce Pb-206 would be 238 92 U. U - 238 decays into Pb-206 with a half-life of 4.5 * 10^ 9 years. Hope this answers the question. Have a nice day.