## Chemistry: Atoms First (2nd Edition)

1. Calculate the average atomic mass of the element: $$( 0.0140 )( 203.973 \space u)+( 0.2410 )( 205.9745 \space u)+( 0.2210 )( 206.9759 \space u)+( 0.5240 )( 207.9766 \space u)=207.2 \space u$$ 2. Use a periodic table to identify the element with average atomic mass equal to 207.2 u. - It is Pb: Lead.