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NOMENCLATURE NAMING COMPOUNDS (p48-50) 466

Metal & Non-Metal This is an ionic bond. Steps to follow in naming compounds: 1) Name the metallic element first. 2) Then name the second element. 3) Add the ending “ide” to the second element.

Examples MgH2 Magnesium hydride NaCl Sodium chloride Li2S Lithium sulfide K2O Potassium oxide Notice how the little numbers(subscripts) do not affect the way we name the compounds.

Non-Metal & Non-Metal This is a covalent bond. Steps to follow when naming these compounds. 1) Name the more metallic element first. 2) Name the second element with “ide” as the ending. 3) Use prefixes before each element.

PREFIXES

Examples N2O5 dinitrogen pentoxide PCl3 phosphorus trichloride CO carbon monoxide Note that we drop the prefix mono if it appears on the first element.

Practice Questions Give the name of the following compounds: KI Ca3P2 K3O CCl4 N2O3 SCl3

ANSWERS KI Potassium iodide Ca3P2 Calcium phosphide K3O Potassium oxide CCl4 Carbon tetrachloride N2O3 Dinitrogen trioxide SCl3 Sulfur trichloride

Transition Elements The transition elements are chemically quite different from the metals in the “A” block, due to differences in electronic configuration. For example, Fe can loose two or three electrons to become Fe2+ and Fe3+, respectively.

To identify the charge of Fe in a compound the following nomenclature is used. Fe2+ is iron(II) Fe3+ is iron (III) So iron(III) chloride is FeCl3 Cu1+ is copper(I) Cu2+ is copper(II)

More examples with Transition Metals CuCl2 = copper(II) chloride ZnCl2 = zinc (ll) chloride CoBr2 = cobalt(II) bromide Hg2S = mercury(I) sulfide

Practice Questions IF5 BaCl (WRONG!!) Give the formula for each compound: 1) iodine pentafluoride (covalent) IF5 2) Barium chloride (ionic) BaCl (WRONG!!) Ba2Cl1 --> BaCl2 (use crossover) (be careful when dealing with ionic compounds, you must use the crossover rule)