In general "potassium phosphate will have 8 atoms, but WHICH 8 depends on which potassium phosphate you are talking about ("potassium phosphate" refers to all the phosphate salts of potassium).
- Monopotassium phosphate (KH2PO4 ) has 1 potassium, 2 hydrogens, 1 phosphorous and 4 oxygens for a total of 8 atoms
- Dipotassium phosphate (K2HPO4) has 2 potassiums, 1 hydrogen, 1 phosphorous and 4 oxygens, for a total of 8
- Tripotassium phosphate (K3PO4) has 3 potassiums, 1 phosphorous and 4 oxygens, for a total of 8 atoms
