Answer
It changes into Pb (lead)
Work Step by Step
unbalanced equation : 210/84 Po => ? + 4/2 He
we can replace ? with a/b Z, where:
a= the atomic number
b= the mass number
Z= the symbol of the element
The main point is that the sums of the superscripts and the subscripts needs to be the same on the each side of the equation.
So,
210=a+4
a=206
84=b+2
b=82
Element with the mass number 82 is lead, and the equation looks like this:
210/84 Po => 206/82 Pb + 4/2 He
