Question

What is Y? 222/86 Rn A/z + 4/2He

Answer 1

`^(222)_{\phantom{2}86}\text{Rn} \to ^(218)_{\phantom{2}84}\text{Po}+ ^(4)_(2)\text{He}`

Y is Po-218.

• A = 218
• Z = 84.

Explanation

`^(222)_{\phantom{2}86}\text{Rn} \to ^(A)_(Z)\text{Y}+ ^(4)_(2)\text{He}`

Here's the symbol of a particle in a nuclear reaction.
`^(A)_(Z)\text{Y}`.

A stands for mass number. Z stands for atomic number. Both numbers shall conserve in a nuclear reaction.

• The mass number on the left hand side is 222.
• The two mass numbers on the right hand side add up to A + 4.
• 222 = A + 4.
• A = 218

So is the case for the atomic number. Try figure out the atomic number of Y using the same approach.

• The atomic number on the left hand side is 86.
• The two atomic number on the right hand side add up to __ + __.
• 86 = __ + __.
• Z = 84.

What element is Y? The atomic number of Y is 84. Refer to a periodic table. Element 84 corresponds to Po (polonium). Y is Polonium-218. The symbol of Y should be written as
`^(218)_{\phantom{2}84}\text{Po}`. Hence the equation:

`^(222)_{\phantom{2}86}\text{Rn} \to ^(218)_{\phantom{2}84}\text{Po}+ ^(4)_(2)\text{He}`.