A radioactive nucleus ‘A’ undergoes a series of decays according to the following scheme:

The mass number and atomic number of A are 180 and 72 respectively. What are these numbers for A 4 ?

Solution:

A has mass number as 180 and atomic number 172 .

Formation of A 1 by α-decay:

Formation of A 2 by β decay:

Formation of A 4 :

In r -decay, mass number and atomic number remain the same.

Thus,

Mass number of A 4 = 172

Atomic number of A 4 ­ = 169

some mistake kindly check....

please check the atomic no its not 172 but it is 72.the procedure is correct go ahead

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