Answer is : beta (minus) decay.
Beta decay is radioactive decay in which a beta ray and a neutrino are emitted from an atomic nucleus.
There are two types of beta decay: beta minus and beta plus.
In beta minus decay (this example), neutron is converted to a proton, an electron and an electron antineutrino and decay atomic number Z is increased by one.
Nuclear equation: 51/24Cr → 61/25Mn+ 0/+1e.
