The atomic masses of 204pb (1.4 percent), 206pb (24.1 percent), 207pb (22.1 percent), and 208pb (52.4 percent)are 203.973020, 205.974440, 206.975872, and 207.976627 amu, respectively. calculate the average atomic mass of lead. the percentages in parentheses denote the relative abundances.

207amu

Explanation:

To calculate the average atomic mass of an element you must multiply the masses of its isotopes with the percent abundance divided by 100. Then you add them together for your answer.

203.973020amu × 0.014 = 2.9amu

205.974440amu × 0.241 = 49.6amu

206.975872amu × 0.221 = 45.7amu

207.976627amu × 0.524 = 109amu

2.9 + 49.6 + 45.7 + 109 = 207amu

the answer is d. 74.02