An isotone of `._(32)^(76)Ge` is
(i) `._(33)^(77)As` (ii) `._(34)^(77)Se`
(iii) `._(34)^(78)Se` (iv) `._(32)^(77)Ge`

Options

A. `(i),(iii)`
B. `(ii),(iv)`
C. `(i),(iv)`
D. `(iii),(iv)`

Answer

A

Explanation

Isotones are the atoms of different elements containing the same number of neutrons. They differ in atomic number as well as mass number. Number of neutrons `(N)` is equal to mass number `(A)` minus atomic number `(Z)`.
`._(32)^(76)Ge (N = 44), _(33)^(77)As(N = 44), _(34)^(77)Se(N = 43)`
`._(34)^(78)Se (N = 44), _(32)^(77)Ge (N = 45)`