The product of electron capture decay of argon isotope ³⁷Ar can be seen in the equation shown below:
³⁷₁₈Ar+⁰₋₁e------>³⁷ ₁₇Cl +υ
During electron capture, nucleus captured a inner orbital electron and results in a formation of a neutron that combines with proton. Mass number remain conserved and only atomic number decreases.
Fe: 2+
Br: 1-
Checked on the periodic table
