Answer:
The identity of the element can be determined by comparing the atomic masses of the known isotopes with the atomic masses of the elements listed in the answer choices.
The weighted average atomic mass of the element can be calculated as follows:
(0.51839 × 106.91 amu) + (0.48161 × 108.90 amu) = 107.87 amu
The closest match to this atomic mass is option 1, Silver. The atomic number of silver is 47, which means it has 47 protons in its nucleus. The two stable isotopes of silver are ^107Ag and ^109Ag, which have atomic masses of 106.905 amu and 108.905 amu, respectively. The given atomic masses of the isotopes in the question are not exact matches to the known isotopes of silver, but they are close enough to identify the element as silver.
Therefore, the answer is 1. Silver.