1. Not finding help here? Sign up for a free 30min 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!

Given properties of nucleus, find its atomic number, mass, and element symbol.

  1. Apr 28, 2009 #1
    1. The problem statement, all variables and given/known data

    An unknown nucleus contains 71 neutrons and has twice the volume of the nickel http://www.webassign.net/www32/symImages/f/1/3dca243bf11d1adbce4ca198d1973f.gif nucleus. Identify the unknown nucleus.

    2. Relevant equations

    r = (1.2X10^-15)(A^(1/3))
    V= (4/3)(pi)(r)^3

    3. The attempt at a solution

    I plugged 59 into the radius equation and got "4.6715957X10^-15 m"
    I then plugged that r value into the volume equation which yielded "4.270555X10^-43"

    Since the unknown nucleus is twice the volume of the Ni nucleus, I doubled that volume (getting 8.54111078X10^-43), plugged it into the volume equation to solve for r and got "5.8858 X 10^-15".

    Then I plugged that into the original radius equation to solve for A. I keep getting "14.71" which doesn't make any sense to me.

    Thanks in advance!
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
    Last edited by a moderator: Apr 24, 2017
  2. jcsd
  3. Apr 28, 2009 #2
    Ah i figured it out, nvm.

    When I got to the --4.904836 = Cuberoot(A)-- I was supposed to cube the left side of the equation (yeilding 118 as the atomic mass number) but I was tripling it.

    Duh!

    :-)
     
  4. Apr 28, 2009 #3

    rl.bhat

    User Avatar
    Homework Helper

    An unknown nucleus contains 71 neutrons
    So for the first nucleus r = (1.2X10^-15)[(71 + Z)^(1/3)] where Z is the number of protons.
    Instead of finding radius you can wrote V = k*r = k*A
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Given properties of nucleus, find its atomic number, mass, and element symbol.
Loading...