Question

Iodine-131 is a radioactive isotope. after 7.00 days, 54.7% of a sample of 131i remains. what is the half-life of 131i?

Answer 1

Iodine-131 has a half-life of 8 days.

Answer 2

The half-life of ¹³¹I is 8.04 days.

Step-by-step explanation:

We can calculate the half-life of 131I using the formula:

• 0.547 = (0.5)
  `^(7.00/\alpha )`

Where 0.547 is the percentage of the sample that remains, 7.00 is the amount of days that have passed, and α is the half-life.

We use Log on both sides of the equation:

• -0.262 = -0.301 * (7.00 / α)

And solve for α:

α = 8.04 days