Which of the following sets does not contain isoelectronic species ?

(1) BO33−,CO32−,NO3−⇒ All have 32 electrons in them (2) SO32−,CO32−,NO3−⇒SO32− have 42 electrons in them while CO32−,NO3−have 32 electrons in them (3) CN−,N2,C22−⇒ All have 14 electrons in them (4) PO43−,SO42−,ClO4−⇒ All have 50 electrons in them