Please Help Me!! Im Desperate!!
Which of these pairs of elements is most likely to be part of a polyatomic ion?
A) Li and I
B) Mg and Br
C) K and F
D) S and O

Question

Please Help Me!! Im Desperate!! 
Which of these pairs of elements is most likely to be part of a polyatomic ion?
A) Li and I
B) Mg and Br
C) K and F
D) S and O

zale101 · Answer

http://www.iun.edu/~cpanhd/C101webnotes/chemical-nomenclature/images/polyions.jpg

zale101 · Answer

Which of these choices are most commonly used in the chart i linked above?
A Polyatomic ion is usually covalently bonded with group of nonmetallic atoms.

danjs · Answer

If you recall , most of the multi atom ions are the Anions...
A Few of the common ones , if you recall are...

Sulfate - SO4
Carbonate - CO3
Bi-Carbonate - HCO3
NITRATE - NO3

It looks so far that many of the common multi-atom anions have oxygen in them. Looking at a larger chart of many common polyatomic ions, you can see that Oxygen is included in the majority. That leaves you with one choice as your answer.