Which is the first element in the periodic table with an atomic mass greater than 100?

• A. Ruthenium (Ru)
• B. Silver (Ag)
• C. Rhodium (Rh)
• D. Molybdenum (Mo)

Answer: (B)

Verified step by step guidance

1. Understand that the atomic mass of an element is the average mass of its atoms, measured in atomic mass units (amu), and it generally increases as you move to elements with higher atomic numbers in the periodic table.
2. Identify the atomic masses of the given elements: Molybdenum (Mo), Ruthenium (Ru), Rhodium (Rh), and Silver (Ag) by consulting a reliable periodic table or reference source.
3. Compare the atomic masses of these elements to determine which one is the first (i.e., has the lowest atomic number) with an atomic mass greater than 100 amu.
4. Note that Molybdenum (Mo) has an atomic mass just under 100 amu, while Ruthenium (Ru) and Rhodium (Rh) have atomic masses slightly above 100 amu, but Silver (Ag) has a higher atomic number and an atomic mass greater than 100 amu.
5. Conclude that among the options, Silver (Ag) is the first element in the periodic table with an atomic mass greater than 100, based on its position and atomic mass values.