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isotopic abundance - practice problems. The atomic mass for each element appearing on the periodic table represents the weighted average of masses for each individual isotope of an element. For example, the atomic mass of carbon is reported as 12.011 amu (atomic mass units).
The average atomic mass of an element can be determined from the relative amounts of each isotope. This is the mass used in most chemical calculations. In a naturally occurring element, the fractional abundance is the percentage of the abundance of a
1. Four isotopes of lead include lead-204, lead-206, lead-207, and lead-208. The average atomic mass of a lead atom is 207.2 amu. Which isotope of lead is likely to be the most abundant? 2. What do all isotopes of an element have in common? 3. Explain why carbon-14 and nitrogen-14 are not considered isotopes. 4.
Based on the atomic mass, which isotope should be more abundant? Answer: The atomic mass of boron is 10.811; therefore, boron-11 is more abundant because the mass number is closer to the atomic mass. 8. Lithium-6 is 4% abundant and lithium-7 is 96% abundant. What is the average mass of lithium? Answer: 6.96 amu 9.
Average atomic masses listed by IUPAC are based on a study of experimental results. Bromine has two isotopes, 79 Br and 81 Br, whose masses (78.9183 and 80.9163 amu) and abundances (50.69% and 49.31%) were determined in earlier experiments.
Chemistry: Average Atomic Mass Worksheet. Calculate the average atomic mass for each element based on the natural abundance of its isotopes. Find the average atomic mass for Li if 7.5% of Li atoms are 6Li with a mass of 6.0151223 amu and 92.5% are 7Li with a mass of 7.0160041 amu.
Average Atomic Mass Worksheet: show all work. 1) Rubidium is a soft, silvery-white metal that has two common isotopes, 85Rb and 87Rb. If the abundance of 85Rb is 72.2% and the abundance of 87Rb is 27.8%, what is the average atomic mass of rubidium? 2) Uranium is used in nuclear reactors and is a rare element on earth. Uranium has three common ...
