How do you write a balanced nuclear equation for the alpha decay of radioactive isotopes?

Write a balanced nuclear equation for the alpha decay of each of the following radioactive isotopes:

A. curium-243
B. Th -Atomic Mass Number: 232, -Atomic Number: 90
C. No -Atomic Mass Number: 251, -Atomic Number: 102
D. radon-220

1 Answer
Oct 26, 2017

An alpha particle is 2 protons and 2 neutrons for a total of 4 nucleons. We can write it as #"_2^4alpha# or #"_2^4He#, since this is like a helium-4 nucleus.

See below the balanced equations for these 4 alpha decays.

Explanation:

A. curium-243

#"_96^243Cm##-> _94^239Pu + "_2^4alpha#

B. Th -Atomic Mass Number: 232, -Atomic Number: 90

#"_90^232Th##-> _88^228Ra + "_2^4alpha#

C. No -Atomic Mass Number: 251, -Atomic Number: 102

#"_102^251No##-> _100^247Fm + "_2^4alpha#

D. radon-220

#"_86^220Rn##-> _84^216Po + "_2^4alpha#