What happens with the ions (cations, anions, and spectator ions) in the precipitate reaction of Potassium Iodide being added to Lead Nitrate?

Question

anonymous · Answer

https://www.youtube.com/watch?v=M0sKFmcOPZk Here's a link to the reaction

chmvijay · Answer

did u see that video ?

anonymous · Answer

Yes.  If I had to guess what was happening, I'd say it is a double displacement reaction in which the lead is replacing the potassium and combing with iodide while the potassium is replacing the lead and combining with the nitrate.  This would form the precipitate which would be Lead (II) Iodide, which has a yellow color.  Is that correct?  Also, what role do the spectator ions play in this?