Q28 / 180 · AIIMS 2014 · Chemistry

Which of the following pairs represent isotones?

Correct answer
A
${ }_{33}^{77} \mathrm{As},{ }_{34}^{78} \mathrm{Se}$
B
${ }_{78}^{195} \mathrm{Pt},{ }_{76}^{190} \mathrm{Os}$
C
${ }_{47}^{108} \mathrm{Ag},{ }_{48}^{112} \mathrm{Cd}$
D
${ }_{72}^{178} \mathrm{Hf},{ }_{56}^{137} \mathrm{Ba}$

Solution

Isotones have the same number of neutrons. As $=77-33=44 ; \mathrm{Se}=78-34=44$

Hence, the correct answer is option: 'A'.

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