AMU Medical AMU Solved Paper-2009

  • question_answer
    Arrange in decreasing order, the energy of 2s orbital in the following atoms H, Li, Na, K

    A)  \[{{E}_{2s(H)}}>{{E}_{2s(Li)}}>{{E}_{2s(Na)}}>{{E}_{2s(K)}}\]

    B)  \[{{E}_{2s(H)}}>{{E}_{2s(Na)}}>{{E}_{2s(Li)}}>{{E}_{2s(K)}}\]

    C)  \[{{E}_{2s(H)}}>{{E}_{2s(Na)}}={{E}_{2s(K)}}>{{E}_{2s(Li)}}\]

    D)  \[{{E}_{2s(K)}}<{{E}_{2s(Na)}}<{{E}_{2s(Li)}}>{{E}_{2s(H)}}\]

    Correct Answer: A

    Solution :

                     The electronic configuration of the given atoms is as                 \[H=1{{s}^{1}}\]                 \[Li=1{{s}^{2}},2{{s}^{1}}\]                 \[Na=1{{s}^{2}},2{{s}^{2}}2{{p}^{6}},3{{s}^{1}}\]                 \[K=1{{s}^{2}},2{{s}^{2}}2{{p}^{6}},3{{s}^{2}}3{{p}^{6}},4{{s}^{1}}\] Thus, the increasing order of energy of 2s orbitals is \[{{E}_{2s(K)}}<{{E}_{2s(Na)}}<{{E}_{2s(Li)}}<{{E}_{2s(H)}}\]


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