To name binary compounds in chemistry, you typically follow a set of rules based on the elements present in the compound. Here are the general guidelines:

1. Ionic Compounds:
   • Identify the cation (positively charged ion) and anion (negatively charged ion) in the compound.
   • Write the name of the cation first, followed by the name of the anion.
   • For cations with variable charges, use Roman numerals in parentheses after the cation name to indicate the charge.
   • For anions, change the ending of the element name to “-ide.”
   • Examples: NaCl (sodium chloride), FeCl3 (iron(III) chloride), CaO (calcium oxide)
2. Covalent Compounds:
   • Identify the elements present in the compound.
   • Use prefixes to indicate the number of atoms of each element.
   • The first element does not require a prefix if there is only one atom.
   • The second element always requires a prefix.
   • Change the ending of the second element to “-ide.”
   • Examples: CO2 (carbon dioxide), N2O5 (dinitrogen pentoxide), PCl3 (phosphorus trichloride)

Note: There are some exceptions and additional rules for certain compounds, such as acids, polyatomic ions, and transition metal compounds. It is important to consult a reliable source or your chemistry teacher for specific compound naming rules.