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What evidence indicates that the nuclei of strontium-90 atoms are unstable?*

The stability of an isotope is related to its ratio of*

The stability of isotopes is related to the ratio of which particles in the atoms?*

Which statement describes the stability of the nuclei of potassium atoms?*

Radiation is spontaneously emitted from hydrogen-3 nuclei, but radiation is not spontaneously emitted from hydrogen-1 nuclei or hydrogen-2 nuclei. Which hydrogen nuclei are stable?*

Nuclei of U-238 atoms are*

A change in the nucleus of an atom that converts the atom from one element to another element is called*

In which reaction is an atom of one element converted into an atom of another element?*

Given the equation representing a reaction:

Which type of reaction is represented by this equation?*

Base your answers to questions 10 on the information below and on your knowledge of chemistry.

The isotope Rn-222 is produced by the decay of uranium in Earth’s crust. Some of this isotope leaks into basements of homes in areas where the ground is more porous. An atom of Rn-222 decays to an atom of Pb-206 through a series of steps as shown on the graph below.

Explain, in terms of elements, why the decay of Bi-210 is considered a transmutation.*

Base your answers to questions 11 on the information below and on your knowledge of chemistry.

A nuclear reaction is represented by the equation below.

^{3}_{1}H → ^{3}_{2}He + ^{0}_{−1}e

Explain why the equation represents a transmutation.*

Base your answers to questions 12 on the information below and on your knowledge of chemistry.

When uranium-235 nuclei are bombarded with neutrons, many different combinations of smaller nuclei can be produced. The production of neodymium-150 and germanium-81 in one of these reactions is represented by the equation below.

Germanium-81 and uranium-235 have different decay modes. Ge-81 emits beta particles and has a half-life of 7.6 seconds.

Explain, in terms of nuclides, why the reaction represented by the nuclear equation is a fission reaction.*

Base your answers to questions 13 on the information below and on your knowledge of chemistry.

One fission reaction for U-235 is represented by the balanced nuclear equation below.

Both radioisotopes produced by this fission reaction undergo beta decay. The half-life of Xe-140 is 13.6 seconds and the half-life of Sr-94 is 1.25 minutes.

Explain, in terms of both reactants and products, why the reaction represented by the nuclear equation is a fission reaction.*

Base your answers to questions 14 on the information below.

Nuclear fission has been used to produce electricity. However, nuclear fusion for electricity production is still under development. The notations of some nuclides used in nuclear reactions are shown in the table below.

Compare the atomic masses of nuclides used in fusion to the atomic masses of nuclides used in fission.*

Base your answers to questions 15 on the information below and on your knowledge of chemistry.

Phosphorus-30 and phosphorus-32 are radioisotopes. Phosphorus-30 decays by positron emission.

Complete the equation in your answer booklet for the decay of phosphorus-30 by writing a notation for the missing product.*