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Homework Help: How to calculate the mass of a hydrogen atom

  1. Sep 16, 2015 #1
    • Please post this type of questions in HW section using the template.
    The answer according to my booklet is 1.6734×10-24 (g), but I don't understand how we got this answer.

    proton: 1.6725×10-24
    neutron: 1.6748×10-24
    electron: 0.0009×10-24

    To get the mass, I added protons with neutrons, but I got 3.3473×10-24.

    What am I doing wrong?
  2. jcsd
  3. Sep 16, 2015 #2


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    Staff: Mentor

    Why do you think there is a neutron present?
  4. Sep 16, 2015 #3
    Because the mass number is the sum of protons and neutrons, correct?


    I realised that hydrogen doesn't have any neutrons, so we should only consider the protons. But that still gives the wrong answer.

    And when I subtract the number of protons from the answer, I get 9x10-28, and I can't figure out where this number came from.
    Last edited: Sep 16, 2015
  5. Sep 16, 2015 #4


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    Staff Emeritus
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    Homework Helper

    Do you think that the mass of a hydrogen atom might be affected by the presence of another particle, perhaps? Hint: Look at the list in the OP.
  6. Sep 25, 2015 #5
    Hello? The hydrogen you created is a postively charged atom a which not good. soo
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