Final answer:
An ion's electrical charge is represented by a right superscript next to the element symbol. The Stock system uses roman numerals to distinguish multiple charges of an element. In writing formulas, the crisscross method ensures ions combine in a way that results in a neutral compound.
Step-by-step explanation:
When using the rules for chemical notation, an ion's electrical charge is represented as a right superscript next to the element symbol. For monovalent ions, the charge sign (+ or -) alone is used, omitting the number 1. For ions with multiple charges, the numerical value precedes the sign (e.g., 2+ or 3-). For instance, the sodium ion is denoted as Na+, and the calcium ion is denoted as Ca2+.
In the naming of an ion, the Stock system may be utilized to distinguish between multiple common positive charges of an element by placing a roman numeral indicating the charge after the element's name. Something like Fe2+ would be called the iron(II) ion. This approach emphasizes that sodium is simply referred to as the sodium ion since it only forms a 1+ ion, thereby avoiding confusion.
When writing the formula of a binary ionic compound, the crisscross method is often employed. The numerical value of one ion's charge serves as the subscript for the other ion in this compound. Through this method, the chemical formula reflects the balance of total positive and negative charges, to represent a compound that is electrically neutral as a whole.