The electron configuration of manganese is
Mn: 1s2 2s2 2p6 3s2 3p6 3d5 4s2
Manganese is located in period 4, group 7 of the periodic table and has an atomic number equal to 25 that implies neutral manganese atom must have 25 electrons surrounding its nucleus.
The 2 electrons that are lost when the manganese(II) cation is formed are coming from the 4s orbital, which is higher in energy than the 3d orbitals when filled.
The electron configuration of the manganese(II) cation will be
Mn2+: 1s2 2s2 2p6 3s2 3p6 3d5