Answer :
Answer:
a. 28.08 amu
b. Silicon
Explanation:
Step 1: Given data
Isotope Isotopic mass (mi) Fractional abundance (abi)
²⁸X 27.977 amu 0.9221
²⁹X 28.976 amu 0.0470
³⁰X 29. 974 amu 0.0309
Step 2: Calculate the atomic weight (aw) of this element
We will use the following expression.
aw = ∑mi × abi
aw = 27.977 amu × 0.9221 + 28.976 amu × 0.0470 + 29. 974 amu × 0.0309
aw = 28.08 amu
Looking at the periodic table, the element with atomic weight = 28.08 amu is silicon.