0.132-g sample of Fe-29 (half-life is 44.5 days) is allowed to decay for 265 days. What quantity of this beta-emitter remains

Ruthenium-106 (106Ru) is used to treat melanoma in the eye. This isotope decays by β– emission with a half-life of 373.59 days. One source of the isotope is reprocessed nuclear reactor fuel. How many protons and neutrons does the 106Ru nucleus contain? Identify the missing daughter nucleus in the β– emission decay of 106Ru below. How many years after 106Ru is implanted in the eye does it take for its decay rate (or activity) to be reduced to 27.5% of the initial decay rate? Use 1 year = 365 days.

All the disintegrations of a sample of an unknown nuclide weighing 4.6 x 10-2 g were counted. In the first half-life of the sample, the total number of disintegrations counted was 4.3 x 1020. What is the atomic weight of the unknown element?

The half-life of Sr-90 is 28 years. After 56 years of decay only 0.40 g of a sample remains. What was the mass of the original sample?

An unknown radioactive substance is currently decaying. Initially, the sample contained 17.8g of the substance. After 5.00 hours of decay, 3.4g of the substance remain. What is the half-life (t1/2) of the substance?

The Cs-131 nuclide has a half-life of 30 years. After 120 years, 2.2 g remain. What is the original mass of the Cs-131 sample in grams?

A moon rock collected by a U.S. Apollo mission is estimated to be 4.10 billion years old by uranium/lead dating. Assuming that the rock did not contain any lead when it was formed, what is the current mass of 20Pb in the rock, if it currently contains 1.385 g of 238 U? The half-life of 238U is 4.47 x 10° years. 0.734 206 Pb mass: torormrt

Bi−210 is a beta emitter with a half-life of 5.0 days If a sample contains 1.0 g of Bi−210, how many beta emissions would occur in 5.0 days?

The Cs-131 nuclide has a half-life of 30 years. After 120 years, 2.5 g remain. What is the original mass of the Cs-131 sample in grams?