Lead and bismuth are the most massive naturally occurring elements;

Every nucleus more massive than them eventually decays into one form or another
of lead or bismuth. The sequence of isotopes along the way forms a decay
series or disintegration series.
For two points per series, given the final form of each series and the number
of alpha (á) and beta (â-) decays, determine the starting nuclide of each
series and enter it below. On the bottom and back of the paper, show one
set of the steps along the way for each series. Don’t just Google the answer,
but work out one of the many, many possibilities for each series.

Final
nuclide

Number of
á decays

Number of
â- decays

lead-208

6

4

bismuth-209

8

5

lead-206

8

6

lead-207

7

4

Initial
nuclide

Lead and bismuth are the most massive naturally occurring elements;

Every nucleus more massive than them eventually decays into one form or another
of lead or bismuth. The sequence of isotopes along the way forms a decay
series or disintegration series.
For two points per series, given the final form of each series and the number
of alpha (á) and beta (â-) decays, determine the starting nuclide of each
series and enter it below. On the bottom and back of the paper, show one
set of the steps along the way for each series. Don’t just Google the answer,
but work out one of the many, many possibilities for each series.

Final
nuclide

Number of
á decays

Number of
â- decays

lead-208

6

4

bismuth-209

8

5

lead-206

8

6

lead-207

7

4

Initial
nuclide

Lead and bismuth are the most massive naturally occurring elements;

Every nucleus more massive than them eventually decays into one form or another
of lead or bismuth. The sequence of isotopes along the way forms a decay
series or disintegration series.
For two points per series, given the final form of each series and the number
of alpha (á) and beta (â-) decays, determine the starting nuclide of each
series and enter it below. On the bottom and back of the paper, show one
set of the steps along the way for each series. Don’t just Google the answer,
but work out one of the many, many possibilities for each series.

Final
nuclide

Number of
á decays

Number of
â- decays

lead-208

6

4

bismuth-209

8

5

lead-206

8

6

lead-207

7

4

Initial
nuclide