To determine the identity of the element with the given average atomic mass, we should compare the average atomic mass with the known atomic masses of the elements listed (nickel, aluminum, silicon, and neon). The goal is to find the element whose atomic mass is closest to the given average atomic mass of 28.085 amu.
Let's compare each element's atomic mass to this value:
1. Nickel (Ni) has an atomic mass of 58.6934 amu, which when compared to 28.085 amu, the difference is 58.6934 - 28.085 = 30.6084 amu.
2. Aluminum (Al) has an atomic mass of 26.9815385 amu, which when compared to 28.085 amu, the difference is |26.9815385 - 28.085| ≈ 1.1034615 amu.
3. Silicon (Si) has an atomic mass of 28.085 amu, which when compared to 28.085 amu, the difference is |28.085 - 28.085| = 0 amu. This element's atomic mass is exactly the same as the given average atomic mass.
4. Neon (Ne) has an atomic mass of 20.1797 amu, which when compared to 28.085 amu, the difference is |20.1797 - 28.085| ≈ 7.9053 amu.
Based on these comparisons, the element whose atomic mass is identical to the given average atomic mass is silicon. Thus, the identity of the element is Item 3: silicon.
