Answer: [tex]_{38}^{90}\textrm{Sr}\rightarrow _{36}^{86}\textrm{Kr}+_2^4\textrm{He}[/tex]
Explanation:
Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.
General representation of an element is given as: [tex]_Z^A\textrm{X}[/tex]
where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
General representation of alpha decay :
[tex]_Z^A\textrm{Sr}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha[/tex]
The balanced nuclear equation when the isotope Strontium-90 decays by Q- decay is :
[tex]_{38}^{90}\textrm{Sr}\rightarrow _{36}^{86}\textrm{Kr}+_2^4\textrm{He}[/tex]