Q2. Fill in the missing isotopic data of Antimony (Sb) in the following table.

Background

Topic: Isotopes and Atomic Mass

This question tests your understanding of isotopes, their notation, and how to interpret and complete isotopic data tables. You are expected to use the information given (isotopic mass and abundance) to deduce the missing isotope and its properties.

Key Terms and Formulas

• Isotope: Atoms of the same element with different numbers of neutrons (and thus different mass numbers).

• Isotopic Mass (amu): The mass of a specific isotope, measured in atomic mass units (amu).

• Abundance (%): The relative amount of each isotope found in nature, expressed as a percentage.

• Isotope Notation: , where is the mass number and is the chemical symbol.

Step-by-Step Guidance

1. Examine the table: One isotope is with a mass of 120.9038 amu. The other isotope's mass number and mass are missing, but its abundance is 42.79%.

2. Recall that naturally occurring antimony has two main isotopes: and . The missing isotope should be $ ^{123}\mathrm{Sb} $.

3. To complete the table, you need to fill in the isotopic mass for . This value is typically found in reference tables or periodic tables.

4. Check the abundance for : Since the total abundance must add up to 100%, subtract the given abundance (42.79%) from 100% to find the abundance of $ ^{121}\mathrm{Sb} $.

5. Now, match the correct isotopic mass and abundance to the correct isotope, using the answer choices provided.

Try solving on your own before revealing the answer!