Writing | Formulas -criss-cross Method-

Place the metal (cation) first and the non-metal (anion) second. Include their ionic charges as superscripts. Example: Aluminum ( cap A l raised to the 3 plus power ) and Oxygen ( cap O raised to the 2 minus power The "Criss-Cross": numerical value of the charge from one ion and move it to the of the other ion. Drop the (+) and (–) signs. The 3 from moves to the bottom of The 2 from moves to the bottom of Simplify (Reduce):

Ionic compounds are neutral. This method finds the lowest ratio of ions needed so the total positive charge equals the total negative charge. 1. Write the Symbols writing formulas -criss-cross method-