Answer:
Step-by-step explanation:
The missing number in the nuclear reaction can be determined by analyzing the conservation of mass and charge.
In the given reaction, Pt → He + ? + Os, the atomic number (proton number) on the left side is 78 (Pt) and on the right side is 2 (He) + ? + 76 (Os).
Since the atomic number represents the number of protons in an atom and is conserved in a nuclear reaction, the sum of the atomic numbers on the right side should equal the atomic number on the left side.
Therefore, 2 + ? + 76 = 78.
To solve for the missing number, we can subtract 2 and 76 from both sides of the equation:
? = 78 - 2 - 76
? = 0
Hence, the missing number in the nuclear reaction is 0.