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Question:

vjoane13
vjoane13
Student
High School - 9th Grade

How do you figure out the number of neutrons in a atom?

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Posted by vjoane13 on Wednesday October 28, 2009 at 2:13 PM and tagged with atom, isotope, neutron.

Answers:


  1. pohnpei397 Teacher
    Community / Jr. College

    eNotes Editor

    Atoms are all made up of three kinds of subatomic particles.  These are electrons, which have negative charges, protons, which have positive charges, and neutrons, which are neutral.  The protons and neutrons make up the nucleus of the atom while the electrons orbit the nucleus.

    In order to find the number of neutrons in an atom, take the following steps:

    1.  Look up the element on the Periodic Table.

    2.  Find the atomic number.

    3.  Find the atomic weight.

    4.  Round the atomic weight to the nearest whole number.  This tells you the atomic mass.

    5.  Subtract the atomic number from the atomic mass.  This gives you the number of neutrons in the atom.

    Sources:
    http://education.jlab.org/qa/pen_number.html

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    Posted by pohnpei397 on Wednesday October 28, 2009 at 3:40 PM

  2. canyousee67
    canyousee67 Student
    High School - 9th Grade

    You must find out the Atomic Number and Atomic mass of an element. Lastly, you subtract the atomis# from the atomic mass.

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    Posted by canyousee67 on Wednesday October 28, 2009 at 9:29 PM


  3. enotechris Teacher
    Vocational

    eNotes Editor

    Atoms can have a variable number of neutrons.  That is why the atomic mass is not a whole number; it represents an average weight of all the atoms of an element, which may have different numbers of neutrons. An atom always has the same number of protons, but may have many different numbers of neutrons in the nucleus.  Each of these is known as an isotope of the atom.  So, an atom's proton count always remains the same, but its neutron count may vary.  The second link shows a Periodic Table of Isotopes.  Who knew that hydrogen can have up to 5 neutrons in its nucleus!

     

    Sources:
    http://ie.lbl.gov/education/info.htm
    http://ie.lbl.gov/education/parent/H_iso.htm

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    Posted by enotechris on Thursday October 29, 2009 at 9:03 AM