1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Chemistry - isotpic mass, atomic mass, mass number

  1. Oct 11, 2009 #1
    1. The problem statement, all variables and given/known data

    The two isotopes of antimony have masses 120.90 and 122.90, with a relative abundance of 57.25% and 42.75% respectively. Using these figures, distinguish clearly between atomic mass, isotopic mass, and mass number.

    2. Relevant equations

    3. The attempt at a solution

    I think atomic mass is the relative isotopic abundance which in our case would be

    (0.5725)(120.90) + (.4275)(122.90) = 121.755

    Would isotopic mass be simply 120.90 and 122.90?

    Would mass number be the same as the atomic mass?

    Some how I think I am wrong concerning the last two.
  2. jcsd
  3. Oct 14, 2009 #2


    User Avatar
    Homework Helper

    i think mass number is the total number of protons & neutrons

    the others sound reasonable, but its been a fair while since i've played with this stuff
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook