Iodine- 131 is radioactive and has a half life of 8.04 days. What percentage of a sample would be left after 3.26 days? Round your answer to 2 significant digits.

It is estimated that the Sun contains 9 x 1056 free protons. How many protons per second are consumed in nuclear reactions in the Sun? Express your answer in protons per second to two significant figures.

The radioactive isotope strontium-81 is used in medical imaging as indicated on the table above. If 77.1 milligrams of strontium-81 is administered to a patient, how many milligrams are left in the body after 66.6 minutes?__ mg

Radioactive radon-222, found in many homes, is a potential health hazard. The half-life of radon-222 is 3.82 days. If you begin with 37.9 mg of this isotope, what mass remains after 4.70 days have passed? _____mg

4) How many years old is a person who has lived for 1 billion seconds?

Iodine-131 is radioactive and has a half life of 8.04 days. What percentage of a sample would be left after 30.9 days? Round your answer to 2 significant digits. U % 0 x10

Carbon 11 is a radioactive element with a half-life of 20.3 minutes.  A sample initially contains 1E7 atoms of Carbon 11. How many of those will be left after 285 minutes? Keep four significant digits.

Iodine-125 is radioactive and has a half life of 60.25 days. How much of a 6.70 mg sample would be left after 12.8 days? Round your answer to 2 significant digits. Also, be sure your answer has a unit symbol. 0 0.9 H

Cobalt-60 is radioactive and has a half life of 5.26 years. What percentage of a sample would be left after 5.84 years? Round your answer to 2 significant digits. 0.P X