2. The electrons of the pi-bond are exposed. Because the pi bond results from overlapping p orbital, the pi electrons lie above and below the plane of the double bond Love elctrons Electrophiles亲电试剂 H. X Lewis acids: Bf2 and alcl Metal ions: Agt. Hg2+. pt2+2. The electrons of the pi-bond are exposed. Because the pi￾bond results from overlapping p orbital, the pi electrons lie above and below the plane of the double bond: C C  sp 2 Electrophiles 亲 电 试 剂 H + , X + , Lewis acids; BF3 and AlCl 3 Metal ions; Ag + , Hg 2+ , Pt 2+ , Love elctrons