Question

Can someone please help me:)

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A radon atom has 86 protons, 136 neutrons, and 86 electrons. What will it change to during alpha decay?

An astatine atom with 85 protons, 137 neutrons, and 86 electrons
A francium atom with 87 protons, 135 neutrons, and 86 electrons
A polonium atom with 84 protons, 134 neutrons, and 86 electrons
A radon atom with 86 protons, 136 neutrons, and 85 electrons

Answer 1

We have here Radon Rn with mass number = 86 protons + 136 neutrons = 222. Therefore, we have Rn222. The alpha radiation emits particles in the same size of the He atom whose mass number equals 4. By subtracting 4 from 222 we get 218 which is the mass number of Polonium Po218 with 84 protons and 134 neutrons.
Therefore, the right answer is C.