In the following questions two or more options may be correct.

Which of the following sets contain only isoelectronic ions?


i) Zn2+=30-2=28 Ca2+=20-2=18 Ga3+=31-3=28 Al3+=13-3=10

ii)K+= 19-1=18 Ca2+=20-2=18 Sc3+=21-3=18 Cl-=22-4=18


iii)P3- =15+3=18 S2- =16+2=18 Cl- =17+1=18 K+=19-1=18


iv)Ti4+= 22-4=18 Ar=18 Cr3+=24-3=21 V5+=23-5=18


the second and third are correct options as they have isoelectronic elements.

1