How do you write a balanced nuclear equation for alpha decay of Po-218?

1 Answer
Jul 11, 2017

Here's how you can do that.

Explanation:

When a radioactive nuclide undergoes alpha decay, it emits an alpha particle, 42α, which is essentially the nucleus of a helium-4 atom.

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This means that after the alpha particle is emitted

  • the mass number of the nuclide will decrease by 4 this happens because the alpha particle contains 2 protons and 2 neutrons
  • the atomic number of the nuclide will decrease by 2 this happens because the alpha particle contains 2 protons

You can thus say that you have

218.84Po(2184).(842)X+42α

A quick look in the Periodic Table of Elements will show that the element that has the atomic number equal to

842=82 conservation of charge

is lead, Pb. This means that the resulting nuclide will be lead-214 since its mass number is equal to

2184=214 conservation of mass

The balanced nuclear equation that describes the alpha decay of polonium-218 will look like this

218.84Po214.82X+42α

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