The four isotopes of lead are shown below, each with its percent by mass abundance and the composition of its nucleus. using these data, calculate the approximate atomic mass of lead.

I believe we are given the following dа ta:

82p, 122n, 1.4%

82p, 124n, 24.1%

82p, 125n, 22.1%

82p, 126n, 52.4%

Where p stands for proton and n for neutrons. We know that the mass number (atomic mass) is equivalent to the sum of p and n, hence the atomic mass of each isotope is:

isotope 1: 82 + 122 = 204 amu

isotope 2: 82 + 124 = 206 amu

isotope 3: 82 + 125 = 207 amu

isotope 4: 82 + 126 = 208 amu

The atomic mass of Lead is the sum of the weighted average atomic mass of the isotopes, that is:

atomic mass Lead = 204 * 0.014 + 206 * 0.241 + 207 * 0.221 + 208 * 0.524

atomic mass Lead = 207.241 amu = 207.241 g/mol