1. Alpha decay
Alpha particle is
a ₂⁴He nucleus. When a parent atom emits an alpha particle, the atomic number
reduces by 2 in the formed daughter atom while reducing the mass number by 4. Since
atomic number = proton number, due to the decreasing of atomic number, proton
number also reduces by 2 in daughter nucleus.
2. Beta
emission.
There are two types
of beta decay. One is β⁻ and other one is β⁺ emission.
β⁻ emission
β⁻ emission is an emission of an electron by converting a neutron
to a proton. Hence, in β⁻<span> decay, the atomic
number increases by 1 and
mass number is not changed in the formed daughter nucleus.</span>
β⁺ emission
β⁺ emission is an emission of an positron while converting a
neutron to a proton. Hence, in β⁺ <span>decay, the atomic
number decreases by 1 and mass number is not changed in
the formed daughter nucleus.</span>
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</span>
3. Gamma decay
In Gamma decay there is no any particle decay from the parent nucleus. Unstable nucleus emits energy photon and becomes as stable by undergoing a gamma decay. Hence, there is no change in atomic number or mass number of the daughter atom.
