The half-life of radioactive Technetium-99 is 6.0 hours.Find the number of ⁹⁹Tc nuclei necessary to produce a sample of activity 18 µCi.(1 Ci = 3.7 × 10¹⁰ decays/second) A) 1.2 × 10⁹ B) 3.4 × 10¹¹ C) 8.0 × 10⁸ D) 2.1 × 10¹⁰

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The activity (A) is related to the number of nuclei (N) by the equation A = λN, where λ is the decay constant. λ can be calculated using λ = ln(2) / half-life. For Technetium-99, λ = ln(2) / (6 * 3600 s). The activity is given as 18 µCi, which is 18 * 10^-6 * 3.7 * 10^10 decays/second. Solving for N gives approximately 2.1 × 10^10 nuclei.

The Half-Life of Radioactive Technetium-99 Is 6