Final answer:
When writing the formula for an ionic compound, the cation comes first. The formula consists of the symbol of the cation element followed by the symbol of the anion element.
Step-by-step explanation:
When writing the formula for an ionic compound, the cation comes first. The formula of an ionic compound consists of the symbol of the cation element followed by the symbol of the anion element.
The subscripts in the formula represent the number of atoms of each element in the compound.
For example, in the formula for sodium chloride (NaCl), the cation is sodium (Na) and the anion is chloride (Cl).
When writing the formula for ionic compounds containing polyatomic ions, the same rules apply. The symbol and charge of the cation are written first, followed by the symbol and charge of the anion.
When you write the formula for an ionic compound, the element or polyatomic ion that comes first is the cation, which is typically a metal or a positively charged ion.
This is followed by the anion, which is generally a nonmetal or a negatively charged ion.
If you are including a polyatomic ion in the formula and more than one of these ions is needed, this group should be placed in parentheses with a subscript outside indicating the quantity.
For instance, the correct way to write the formula for calcium nitrate is Ca(NO3)2, not CaNO32 or CaN2O6.
It's essential to ensure that the total positive charge and the total negative charge in the formula are balanced, reflecting a neutral compound overall.