Suppose that half a sample of radioactive nuclei has decayed in a given time T. How long will it be before half the remaining nuclei will have decayed? Explain your reasoning.

A radioactive material has a decay constant of λ = 0.0586 yr-1. If it starts out with N0 = 9.03 × 1018 particles, how many (N) will be left after t = 407 years have gone by? Express your answer in scientific notation. (Example: 1.23e4)

Fusion in the Sun occurs mostly through the proton-proton chain, which starts with the fusion of two protons, 2 H → D+e+ +ve. The second step is the fusion of one of these particles with a third proton to make He-3. a) Name the the three particles created in the first step. b) Write the reaction for the second step

ms tions urse 4. (P7) The isotope Silver-107 undergoes a gamma decay. Write the reaction equation and determine the identity of the daughter nucleus. (P19) A nucleus of element 114 is produced by fusing calcium - 48 with plutonium - 244. Write the reaction equation assuming three neutrons are also released. 5. EC (P20) The most abundant isotope of lithium, Li-7, contains 3 protons and 4 neutrons and has a mass of 7.01600 u. What is the mass defect for this nucleus in atomic mass units? In Kg?

Part A A sample of U (T1= 1.59 × 10° yr) contains 2 233 6.10 x 1018 nuclei. What is the decay constant? Express your answer using three significant figures. ? = s-1 II

Half life of a radioactive isotope is 4x10³ years. If there are 10³ radioactive nudei in a sample today, the number of such nuclei in the sample 4x10⁹ year ago were: (A)128 X10³ (B) 256X10³ (C) 512 X10³ (D) 1024 X10³

The half-life of this nucleus is 1.0 seconds. For the following times fill in the rest of the chart and predict the number of parent nuclei left and the number of new daughter nuclei produced.     Time (seconds) Number of half-lives Parent Nuclei Daughter nuclei 0.0                 Start 100 0 1.0 1 50 50 2.0 2 25 75 3.0 3 12   4.0 4     5.0 5     6.0 6     7.0 7     8.0 8     9.0 9     10 10

Phosphorus has one stable isotope, 31P. The isotope 32P is a neutron-rich radioactive isotope that is used in nuclear medicine. What is the likely daughter nucleus of 32P decay?

The (18 9 F) nucleus is unstable. Draw an energy-level diagram and predict how it will decay.

212, 86 Rn is an odorless gas which decays via alpha decay with a half-life of 24 minutes. a) What's the decay product? b) Show that if you start with 576 grams of radon- 212, two hours later you will have 542 g of the daughter nucleus you found in part a). Note: there are TWO products for this reaction. Mass is conserved over the whole system.