beta decay by
emitting an electron is called as β⁻
decay. When this happens,
a neutron of the element converts into a proton by
emitting an electron. Hence, the
mass of daughter nucleus is
same as parent
atom but
atomic number/number of protons is
higher by 1 than atomic number of
parent atom.
Ni has atomic number as 28.
After β⁻ decay, the daughter nucleus will have
atomic number as 28 + 1 = 29 which belongs to copper.
Decay formula is,
₂₈⁶³Ni → ₂₉⁶³Cu+ ₋₁⁰β
