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BCECE Engineering BCECE Engineering Solved Paper-2012

  • question_answer
    An atom has electronic configuration \[1{{s}^{2}},\text{ }2{{s}^{2}}2{{p}^{6}},3{{s}^{2}}3{{p}^{6}}3{{d}^{3}},4{{s}^{2}}.\]You will place it in

    A)  fifth group     

    B)         fifteenth group

    C)                         second group  

    D)         third group

    Correct Answer: A

    Solution :

    An atom has electronic configuration \[1{{s}^{2}},2{{s}^{2}}2{{p}^{6}},3{{s}^{2}}3{{p}^{6}}3{{d}^{3}},4{{s}^{2}}\] It is a member of d-block element because the last electron is filled in d-subshell as \[3{{d}^{3}}\] and the following electronic configuration is possible for d-subshell as \[(n-1)\]d-subshell
    Group NO. IIIB IVB VB VIB VIIB VIII VIII VIII IB IIB
    (13) (14) (15) (16) 17 (18) (19) (20) (21) (22)
    \[n{{s}^{2}}(n-1){{s}^{2}}{{p}^{6}}\] \[{{d}^{1}}\] \[{{d}^{2}}\] \[{{d}^{3}}\] \[{{d}^{4}}\] \[{{d}^{5}}\] \[{{d}^{6}}\] \[{{d}^{7}}\] \[{{d}^{8}}\] \[{{d}^{9}}\] \[{{d}^{10}}\]
    Hence, it is a member of fifth group


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