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Covalent Nomenclature. Naming Molecular Compounds. Review. How do we identify ionic formulas? Ionic formulas start with metals (or NH 4 +1 ) How do we identify covalent formulas? Covalent formulas contain only non-metals or metalloids. How do we name ionic compounds?
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Covalent Nomenclature Naming Molecular Compounds
Review • How do we identify ionic formulas? • Ionic formulas start with metals (or NH4+1) • How do we identify covalent formulas? • Covalent formulas contain only non-metals or metalloids. • How do we name ionic compounds? • Identify the compound as binary or ternary. • Identify the metal as fixed charge or variable charge. • If the compound is binary, ends in –ide. • If the compound is ternary, name the anion appropriately.
Naming Molecular Compounds • All the molecular compounds you’ll be asked to name are binary. • Molecular compounds w/ more than 2 elements are usually organic. • Organic compounds have their own special naming system. • Atoms in molecules don’t the number of each atom: • mono = 1 • di = 2 • tri = 3 • tetra = 4 • penta = 5 • hexa = 6 • hepta = 7 • octa = 8 • nona = 9 • deca = 10
Naming Molecular Compounds • Prefix for first element in compound. • Omit if it’s “mono”. • Name first element. • Prefix for second element in compound. • Give stem of second element followed by suffix –ide. • Examples: • CO = carbon monoxide • CO2 = carbon dioxide • N2O = dinitrogen monoxide
Details and Exceptions • If the last letter of the prefix and the first letter of the element are both vowels, drop the last letter of the prefix. • CO = carbon monoxide, not carbon monooxide • N2O5 = dinitrogen pentoxide, not dinitrogen pentaoxide • Some compounds are known only by their common names • H2O = water • NH3 = ammonia • CH4 = methane
Writing Formulas From Names • Write symbols in the same order they appear in the name. • Use prefixes to determine subscripts. • Metalloids are not metals. • Compounds that start with metalloids are named as molecular compounds.
Naming Molecular Compounds • What are the names of the following molecular compounds? • NO2 • SO3 • SiO2 • NO • P2O5 • S4N4 nitrogen dioxide sulfur trioxide silicon dioxide nitrogen monoxide diphosphorus pentoxide tetrasulfur tetranitride
Writing Formulas From Names • What are the formulas of the following molecular compounds? • carbon tetrachloride • phosphorus trichloride • selenium dibromide • dinitrogen tetroxide • sulfur dioxide • xenon tetrafluoride • diantimony trioxide CCl4 PCl3 SeBr2 N2O4 SO2 XeF4 Sb2O3