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9th Class Science Structure of the Atom Question Bank 9th CBSE Science Structure of the Atom

  • question_answer
      Composition of the nuclei of two atomic species A and B are given below
      A B
    Protons 17 17
    Neutrons 18 20
    (a) What are the mass numbers A and B? (b) How are they related to each other? Define the term.   

    Answer:

             (a) Mass number of A =No. of protons + No. of neutrons = 17 + 18 = 35 u      Mass number of 5 = 17 + 20 = 37 u (b) They are isotopes of same element. Isotopes are the atoms of same element having the same  atomic number but different mass numbers.


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