Naming and Formula Writing Covalent Compounds Naming and Formula Writing

Covalent Compounds Are made up of two NONMETALS. (Both elements are from the right of the step line (green elements shown)).

Prefixes you need to know One – Mono Two – Di Three – Tri Four – Tetra Five – Penta Six – Hexa Seven – Hepta Eight – Octo Nine – Nona Ten – Deca

Rules for Covalent Compounds #1 – If the compound has only one atom of the first element (no subscript), we just name it normally (do not write mono….). If there are two or more atoms of the first element, we use a prefix to tell how many there are (the subscript). #2 – For the second element, we ALWAYS use a prefix (even mono) and we change then ending of the element to –ide.

For Example… What would you call this compound: CO2? Carbon Dioxide We do not call it Monocarbon Dioxide

Try these SiCl4 C3H9 SO2 N2O5 Silicon tetrachloride Tricarbon nonahydride Sulfur dioxide Dinitrogen pentoxide (you can drop off the –a from penta here so you don’t have to put two vowels together.)

Can you do it in reverse? What is the chemical formula for Dinitrogen Monoxide? N2O Remember, when using prefixes, it tells you the actual subscript, you do not need to determine charges, or criss-cross, etc.

Try these… Carbon disulfide Dinitrogen monosulfide Diphosphorus hexaoxide Tricarbon octachloride CS2 N2S P2O6 C3Cl8