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The numbers of protons and neutrons in each of four different atoms are shown in the table below.
Which two atoms represent isotopes of the same element?*
The nuclides I-131 and I-133 are classified as*
The three nuclides, U-233, U-235, and U-238, are isotopes of uranium because they have the same number of protons per atom and*
An atom that has 13 protons and 15 neutrons is an isotope of the element*
If two atoms are isotopes of the same element, the atoms must have*
Which notations represent atoms that have the same number of protons but a different number of neutrons?*
Which phrase describes two atoms that contain the same number of protons but a different number of neutrons?*
Two atoms that are different isotopes of the same element have*
Base your answers to questions 9 on the information below and on your knowledge of chemistry.
Iodine has many isotopes, but only iodine-127 is stable and is found in nature. One radioactive iodine isotope, I-108, decays by alpha particle emission. Iodine-131 is also radioactive and has many important medical uses.
Explain, in terms of protons and neutrons, why I-127 and I-131 are different isotopes of iodine.*
Base your answers to questions 10 on the information below and on your knowledge of chemistry.
The diagram below shows the first three steps in the uranium-238 radioactive decay series.
The decay mode for the first and third steps is shown above the arrows. The decay mode for the second step is not shown in the diagram. Thorium-234 has a half-life of 24.10 days.
Explain, in terms of neutrons and protons, why U-238 and U-234 are different isotopes of uranium.*
Base your answers to questions 11 on the information below and on your knowledge of chemistry.
Some isotopes of neon are Ne-19, Ne-20, Ne-21, Ne-22, and Ne-24. The neon-24 decays by beta emission. The atomic mass and natural abundance for the naturally occurring isotopes of neon are shown in the table below.
State the number of neutrons in an atom of Ne-20 and the number of neutrons in an atom of Ne-22.*
Base your answers to questions 12 on the information below and on your knowledge of chemistry.
Illuminated EXIT signs are used in public buildings such as schools. If the word EXIT is green, the sign may contain the radioisotope tritium, hydrogen-3. The tritium is a gas sealed in glass tubes. The emissions from the decay of the tritium gas cause a coating on the inside of the tubes to glow.
State, in terms of neutrons, how an atom of tritium differs from an atom of hydrogen-1.*
Base your answers to questions 13 on the information below and on your knowledge of chemistry.
The diagrams below represent four different atomic nuclei.
Explain why nucleus 2 and nucleus 4 represent the nuclei of two different isotopes of the same element.*
Base your answers to questions 14 on the information below and on your knowledge of chemistry.
Cobalt-60 is an artificial isotope of Co-59. The incomplete equation for the decay of cobalt-60, including beta and gamma emissions, is shown below.
Explain, in terms of both protons and neutrons, why Co-59 and Co-60 are isotopes of cobalt.*
Base your answers to questions 15 on the information below and on your knowledge of chemistry.
The table below shows data for three isotopes of the same element.
Explain, in terms of subatomic particles, why these three isotopes represent the same element.*
