Final answer:
When writing a formula for a binary ionic compounds, the cation is always written first.
Step-by-step explanation:
TRUE
When writing a formula for a binary ionic compound, the cation is always written first. The cation is a positively charged ion, usually a metal, and it is named first in the compound formula. The anion, which is a negatively charged ion, usually a nonmetal, is named second.
For example, in the compound sodium chloride (NaCl), sodium is the cation and chlorine is the anion. Sodium, being the cation, is always written first in the formula.
Learn more about Writing formulas for ionic compounds