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RAJASTHAN PMT Rajasthan - PMT Solved Paper-2002

  • question_answer
    An element have atomic weight 40 and its electronic configuration is \[1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}\] . Then its atomic number and number of neutrons will be:

    A)  \[18\] and \[22\]      

    B)  \[22\] and \[18\]

    C)  \[20\] and \[20\]

    D)  \[40\] and \[18\]

    Correct Answer: A

    Solution :

    Given, electronic configuration \[=1{{s}^{2}},2{{s}^{2}}2{{p}^{6}},3{{s}^{2}}3{{p}^{6}}\] and atomic weight \[=40\] Hence, atomic number \[=2+2+6+2+6\]                                 \[=18\] Number of neutrons = atomic weight - atomic number                 \[=40-18=22\]


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