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For each pair of isotopes listed, predict which one is less stable:
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Chemistry
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- Though the common isotope of aluminum has a mass number of 27, isotopes of aluminum have been isolated (or prepared in nuclear reactors) with mass numbers of 24, 25, 26, 28, 29, and 30. How many neutrons are present in each of these isotopes? Why are they all considered aluminum atoms, even though they differ greatly in mass? Write the atomic symbol for each isotope.arrow_forward2.87 What is the heaviest element to have an atomic weight that is roughly twice its atomic number? What does this suggest must he true about the nuclei of atoms with higher atomic numbers?arrow_forwardDefine the term atomic weight. Why might the values of atomic weights on a planet elsewhere in the universe be different from those on earth?arrow_forward
- The following isotopes are important in nuclear power. Write their symbols in the form XZA. a. U-235 b. U-238 c. Pu-239 d. Xe-144arrow_forward2.86 For some uses, the relative abundance of isotopes must be manipulated. For example, a medical technique called boron neutron capture therapy needs a higher fraction of 10B than occurs naturally to achieve its best efficiency. What would happen to the atomic weight of a sample of boron that had been enriched in 10B? Explain your answer in terms of the concept of a weighted average.arrow_forwardCerium is the most abundant rare earth metal. Pure cerium ignites when scratched by even a soft object. It has four known isotopes: 136Ce(atomicmass=135.907amu) ,138Ce(atomicmass=137.905amu) ,140Ce(atomicmass=139.905amu), and142Ce(atomicmass=141.909amu). Ce-140 and Ce-142 are fairly abundant. Which is the more abundant isotope?arrow_forward
- Bromine has two occuring isotopes: 79Br with atomic mass 78.9183 and 81Br with atomic mass 80.9163. Without using a calculator, what would you estimate the % abundance of Br-79 to be?arrow_forward2-103 The element silver has two naturally occurring isotopes: 109Ag and 107Ag with a mass of 106.905 amu. Silver consists of 51.82% 07Ag and has an average atomic mass of 107.868 amu. Calculate the mass of 109Agarrow_forwardWhile traveling to a distant universe, you discover the hypothetical element X. You obtain a representative sample of the element and discover that it is made up of two isotopes, X-23 and X-25. To help your science team calculate the atomic weight of the substance, you send the following drawing of your sample with your report. In the report, you also inform the science team that the brown atoms are X-23, which have an isotopic mass of 23.02 amu, and the green atoms are X-25, which have an isotopic mass of 25.147 amu. What is the atomic weight of element X?arrow_forward
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