Answer:
The atomic weight of X is 28.356 amu
Explanation:
Step 1: Data given
X-28 has an isotopic mass of 27.979 u and an baundance of 77.11%
X-29 has an isotopic mass of 28.976 u and an baundance of 8.00 %
X-30 has an isotopic mass of 29.974 u and an baundance of 14.89 %
Step 2: Calculate the atomic weight of X.
Atomic weight of X = 27.979 * 0.7711 + 0.28.976 * 0.08 + 29.974 *0.1489
Atomic weight of X = 28.356 amu
The atomic weight of X is 28.356 amu