A radioactive atom ' emits a particle to produce an atom ' ' which then emits an -particle to given an (1) The atomic number of ' is less than that of (2) The atomic number of ' ' is less than that of (3) The mass number of ' is same as that of '

Chemistry · Electronic concepts of oxidation and reduction, redox reactions, oxidation number, rules for assigning oxidation number and balancing of redox reactions

A radioactive atom ' emits a particle to produce an atom ' ' which then emits an

A radioactive atom ' \( X^{\prime} \) emits a \( \beta- \) particle to produce an atom ' \( Y \) ' which then emits an \( \alpha \) -particle to given an \( \operatorname{atom}^{\prime} Z^{\prime}: \) (1) The atomic number of ' \( X^{\prime} \) is less than that of \( ^{\prime} Z^{\prime} \) (2) The atomic number of ' \( Y \) ' is less than that of \( ^{\prime} Z^{\prime} \) (3) The mass number of ' \( X^{\prime} \) is same as that of ' \( Y \)

A. 1,2 and 3 are correct
B. 1 and 2 are correct
C. 2 and 3 are correct
D. 3 is correct

Step-by-step solution

Let X have atomic number Z_X and mass number A_X. β- decay increases atomic number by 1 (Z_Y = Z_X + 1, A_Y = A_X). α decay decreases atomic number by 2 and mass number by 4 (Z_Z = Z_Y - 2 = Z_X - 1, A_Z = A_X - 4). Thus: (1) Z_X > Z_Z, so X's atomic number is greater than Z's, not less; (2) Z_Y > Z_Z, so Y's atomic number is greater; (3) A_X = A_Y, so mass numbers are equal. Only statement 3 is correct.

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Step-by-step solution

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