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NEET Sample Paper NEET Sample Test Paper-55

  • question_answer
    An element X decay, first by positron emission and then two \[\alpha -particle\] are emitted in successive radioactive decay. If the product nucleus has a mass number 229 and atomic number 89, the mass number and atomic number of element X are-

    A) 237,93             

    B) 237,94

    C) 221,84             

    D) 237,92

    Correct Answer: B

    Solution :

    \[_{Z}^{A}X\,\to \,_{Z-1}^{A}Y+{{\beta }^{+}}\] \[_{Z-1}^{A}Y\,\to \,_{Z-5}^{A-8}\,M+2\,_{2}^{4}He\] \[A-8=229\,\,\Rightarrow \,\,A=\text{ }237\] \[Z-5=89\,\,\Rightarrow \,\,Z=94\]


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