Naturally occurring element X exists in three isotopic forms: X-28 (27.979 u, 77.11% abundance), X-29 (28.976 u, 8.00% abundance), and X-30 (29.974 u, 14.89% abundance). Calculate the atomic weight of X.

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