Answer:
²³⁵₉₂U
Step-by-step explanation:
Properly writing the equation we have:
²³⁹₉₄Pu → ᵃₙX + ⁴₂He
The unknown atom here is X with mass number "a'' and atomic number ''n''
In balancing chemical equations, the mass number and atomic number must be conserved. This implies that the sum of atomic numbers i.e subscript on the left hand side must be equal to that on the right hand side. Also, the sum of the mass numbers i.e superscript on the left hand side must be equal to that on the right hand side.
For the mass numbers:
239 = a + 4
a = 239 - 4 = 235
For atomic numbers:
94 = n + 2
n = 94 -2 = 92
The atom X, has a mass number of 235 and an atomic number of 92.
This is can be written as ²³⁵₉₂X
This is option 3