Question

Which kind of nuclear decay does not alter the identity of the atom?

Answer 1

For alpha and beta decay it does because the proton number changes.
During gamma, there is no change of identity, just energy

Answer 2

Answer: gamma decay

Explanation:

1. Alpha decay: In this process, alpha particles is emitted when a heavier nuclei decays into lighter nuclei. The alpha particle released has a charge of +2 units.

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}+_2^4\alpha$  

2. Beta-decay: In this process, a neutron gets converted into a proton and an electron releasing a beta-particle. The beta particle released carries a charge of -1 units.

$_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta$

3. Gamma decay: in this process, an unstable nuclei gives off excess energy by a spontaneous electromagnetic process and releases $\gamma -radiations$. These radiations does not carry any charge and are electrically neutral and thus the identity of the atom undergoing gamma decay do not change.

$_Z^A\textrm{X}^*\rightarrow _Z^A\textrm{X}+_0^0\gamma$