To calculate the atomic weight of an element, we use the weighted average of the atomic masses of its isotopes, taking into account their respective abundances.
Given the following isotopes and their abundances:
Isotope 1: Mass = 27.977, Abundance = 0.9221 Isotope 2: Mass = 28.976, Abundance = 0.0470 Isotope 3: Mass = 29.974, Abundance = 0.0309
To calculate the atomic weight:
Atomic weight = (Mass of Isotope 1 x Abundance of Isotope 1) + (Mass of Isotope 2 x Abundance of Isotope 2) + (Mass of Isotope 3 x Abundance of Isotope 3)
Atomic weight = (27.977 x 0.9221) + (28.976 x 0.0470) + (29.974 x 0.0309)
Atomic weight ≈ 25.6929 + 1.3612 + 0.9259
Atomic weight ≈ 27.98
Therefore, the atomic weight of this element is approximately 27.98.
To determine the identity of the element, we can refer to the periodic table and find an element with an atomic weight close to 27.98. In this case, the element with an atomic weight of approximately 27.98 is Aluminum (symbol Al), which has an atomic number of 13.