Answer:
¹⁰₄Be —> ¹⁰₃Li + ⁰₋₁β
Explanation:
To know which equation is unbalanced, we shall compare the mass number and atomic number of the reactant and product together. This is illustrated below:
¹²¹₅₀Sn —> ⁰₋₁β + ¹²¹₅₁Sb
121 = 0 + 121
121 = 121
50 = –1 + 51
50 = 51
Thus the above equation is balanced
¹⁹⁰₇₈Pt —> ¹⁸⁶₇₆Os + ⁴₂α
190 = 186 + 4
190 = 190
78 = 76 + 2
78 = 78
Thus, the above equation is balanced
¹⁰₄Be —> ¹⁰₃Li + ⁰₋₁β
10 = 10 + 0
10 = 10
4 = 3 + (–1)
4 = 3 – 1
4 = 2
Thus, the above equation is unbalanced.
²³⁸₉₂U —> ⁴₂α + ²³⁴₉₀Th
238 = 4 + 234
238 = 238
92 = 2 + 90
92 = 92
Thus, the above equation is balanced.
From the illustrations made above, only ¹⁰₄Be —> ¹⁰₃Li + ⁰₋₁β
Is unbalanced.
