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Homework Help: Isotope problem

  1. Jan 24, 2009 #1
    how would you set this up to solve this problem

    A newly discovered element occurs naturally as the two isotopes: 108X and 114X. In nature 65.8 % of is the isotope 108X and the remaining percentage is 114X. What is the mass number for element X.
  2. jcsd
  3. Jan 24, 2009 #2
    Well basically when giving the mass number for an element, in your case X you take the average of the masses, which obviously changes with the percentages of the respective ones, in this case

    (( 65.8 * 108 ) + ( 34.2 * 114 )) / 100 = It's average mass number which turns out to be 110.05!

    Sorry if I can't explain it that well, but basically, you take the mass of each one * the percentage of it, add them all up, and divide it by 100. If you're still struggling pm me
  4. Jan 24, 2009 #3
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