PROBLEM SET 5, QUESTION 9:

Zirconium has atomic number 40; lead has atomic number 82. (See the Element Tables.) When zirconium loses a proton it becomes element number 39. The alphabetical table shows that this is yttrium (chemical symbol, Y). The mass number of the zirconium also is reduced by 1, so it becomes yttrium-91 (9139Y).

The lead nucleus receives the proton. It becomes a nucleus with atomic number 83; this is bismuth according to the table. The isotope is 208 +1; it is 20983Bi.