Chapter 9: Chemical Names and Formulas Naming and writing formulas for molecular compounds

Determine the name and/or formula of a molecular compound. Learning Target You will: Determine the name and/or formula of a molecular compound.

You will determine the name and/or formula of a molecular compound. Let’s think … How many events are in a triathlon? How do you know that? Prefixes are used in naming molecular compounds. They help distinguish compounds containing different numbers of atoms. You will determine the name and/or formula of a molecular compound.

You will determine the name and/or formula of a molecular compound. Molecular Compounds Recall that ionic compounds are composed of ions of elements - metals and nonmetals. Molecular compounds are also composed of elements but both are nonmetals, not ions. Composed of molecules, not ions, so charges aren’t used for the formula or name. You will determine the name and/or formula of a molecular compound.

You will determine the name and/or formula of a molecular compound. Molecular Compounds Two nonmetals can combine in more than one way. Prefixes help distinguish compounds containing different numbers of atoms of nonmetals. Prefixes tell how many atoms of an element are present in each molecule of the compound. You will determine the name and/or formula of a molecular compound.

You will determine the name and/or formula of a molecular compound. Thinking time … How does a triathlon differ from a pentathlon? How does phosphorus trifluoride differ from phosphorus pentafluoride? A triathlon is composed of 3 sports, while a pentathlon is composed of 5. Phosphorus trifluoride is a binary molecular compound that has 1 phosphorus and 3 fluoride atoms, while phosphorus pentafluoride contains 1 phosphorus and 5 fluoride atoms. You will determine the name and/or formula of a molecular compound.

You will determine the name and/or formula of a molecular compound. Naming and Writing Naming Formulas: First element listed in the formula is named first, using the full element name. Second element listed in the formula is named as an anion. Prefixes are used to tell the number of atoms present. (from the subscripts) 1st element gets a prefix EXCEPT when there is one atom. 2nd element ALWAYS get a prefix. Writing Formulas: Write the element symbols in order listed in the formula. Change the prefixes to subscripts. DON’T assign charges OR cross down Remember if there is no prefix it means the subscript equals one You will determine the name and/or formula of a molecular compound.

Examples CCl4 arsenic trifluoride NO2 dioxygen difluoride IF5 Write the name or formula for the following compounds: CCl4 arsenic trifluoride NO2 dioxygen difluoride IF5 nitrogen monoxide BF3 Silicon dioxide Answers: Carbon tetrachloride AsF3 Nitrogen dioxide O2F2 Iodine pentafluoride NO Boron trifluoride SiO2 You will determine the name and/or formula of a molecular compound.

Write the name or formula for the following compounds: Try on your own Write the name or formula for the following compounds: xenon hexafluoride N2O5 Diphosphorus pentoxide I2O7 Chlorine trifluoride CO2 Nitrogen monoxide CF4 Answers: XeF6 Dinitrogen pentoxide P2O5 Diiodine heptoxide ClF3 Carbon dioxide NO Carbon tetrafluoride

Determine the name and/or formula of a molecular compound. Summarize You will: Determine the name and/or formula of a molecular compound.