We report the structure dependent magnetic and electrical properties of graphitic carbon encapsulated Ni/NiO core/shell nanoparticles synthesized by a sol-gel type processing route. The process allows precise tuning of the magnetic and electrical properties of the derived samples by tailoring the core/shell structure. The samples exhibit non-zero exchange bias (EB) field, HE at room temperature and electrically behave primarily as a semiconductor. However, by controlling the core/shell structure, a metallic behavior associated with a well defined metal to insulator type transition was also observed.