Naming Covalent Compounds

To name a covalent compound, same as ionic naming except you use prefixes to represent how many atoms of each element you have 1 = mono 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexa 7 = hepta 8 = octa 9 = nona 10 = deca

Naming Molecular Compounds write the name of the element that is the least electronegative first. Example: SO2 sulfur

2. Write the name of the second element and change the ending to “ide” Example: SO2 sulfur oxide

3. Add a prefix to the beginning of each element’s name to indicate how many of atoms of each there are (exception: you do not write the word mono in front of the first element if there is only one). Example: SO2 sulfur dioxide

Example: CO Carbon Carbon oxide Carbon monooxide If the vowel combination o-o or a-o appear next to each other in the name, the first of the pair is omitted Example: CO Carbon Carbon oxide Carbon monooxide  carbon monoxide

Practice Problem 1 Name the following molecular compound: CCl4

Practice Problem 2: Name the following molecular compound: N2O4

Exceptions to the naming rule: Hydrocarbons/Organic compounds/Alkanes Compounds made only of carbon and hydrogen and single bonds CH4 = methane C2H6 = ethane C3H8 = propane C4H10 = butane C5H12 = pentane C6H14 = hexane C7H16 = heptane C8H18 = octane C9H20 = nonane C10H22 = decane

If contains double bond alkenes Change ending to –ene ethane ethene If contains triple bond alkynes change ending to –yne Propane  propyne

Exceptions to the naming rule: Common Names H2O = water NH3 = ammonia

Writing Molecular Formulas Name tells you the elements present and the number of each atom to write as subscripts. Example: nitrogen trifluoride

Practice Problem 3: Write the molecular formula for tetraphosphorus decoxide.

Practice Problem 4: Write the molecular formula for dinitrogen monoxide.