silver nitrate is AgNO3 potassium bromide is KBr
Each ion has single charge whether +ve or -ve.
AgNO3(aq) + KBr(aq) = AgBr(s) + KNO3(aq)
AgBr is water insoluble so precipitates. Potassium nitrate is soluble so stays in solution so can also be written as K+(aq) + NO3-(aq)
