aka Naming Compounds Unit 3 Nomenclature aka Naming Compounds Unit 3

Binary Ionic Compounds A two-element compound consisting of a cation and an anion. We will look at two different kinds of binary ionic compounds.

Type I Binary Ionic Compounds The metal present forms only one type of cation. Group 1 and 2 metals are always type I. Na  𝑁𝑎 + Cs  𝐶𝑠 + Ca  𝐶𝑎 2+ Al  𝐴𝑙 3+

Rules for Naming Type I Ionic Compounds The cation is always named first & the anion second A simple cation (obtained from a single atom) takes its name from the name of the element. Ex. 𝑁𝑎 + is called sodium in the names of compounds containing this ion.

Write the name for the compound by combining the names of ions A simple anion (obtained from a single atom) is named by taking the first part of the element name (root) and adding –ide. Ex. 𝐶𝑙 − ion is called chloride. Write the name for the compound by combining the names of ions

Examples: Type I Compounds Ions Present Name NaCl 𝑁𝑎 + , 𝐶𝑙 − Sodium Chloride KI 𝐾 + , 𝐼 − Potassium Iodide CaS 𝐶𝑎 2+ , 𝑆 2− Calcium Sulfide CsBr 𝐶𝑠 + , 𝐵𝑟 − Cesium Bromide MgO 𝑀𝑔 2+ , 𝑂 2− Magnesium Oxide

Practice Give the formulas for the following binary compounds. sodium fluoride NaF lithium sulfide 𝐿𝑖 2 𝑆 calcium bromide Ca 𝐵𝑟 2

Practice Beryllium Fluoride Aluminum bromide Write the names for the following binary compounds. BeF2 Beryllium Fluoride NaI Sodium iodide AlBr3 Aluminum bromide

Practice Radium nitride Strontium Oxide Write the names for the following binary compounds. Ra3N2 Radium nitride K2S Potassium sulfide SrO Strontium Oxide

Type II Binary Compounds The metal present can form two or more cations that have different charges. Follow the same rules for Type I compounds but include a Roman numeral The Roman numeral tells the charge on the ion, not the number of ions present in the compound. Metals that form only one cation do not need to be identified by a Roman numeral.

Ex: Type II Ionic Compounds CuCl Cu = Cation (plus 1 charge) Cl = Anion (negative 1 charge) Name: Copper chloride

Ex: Type II Ionic Compounds HgO Hg = Cation (plus 2 charge) O = Anion (negative 2 charge) Name: Mercury (II) oxide

Rules for Naming: Type III Binary Compounds (Contain Only Nonmetals) The first element in the formula is named first, and the full element name is used. The second element is named as though it were an anion Prefixes are used to denote the numbers of atoms present. These prefixes are given in Table 4.3 The prefix mono- is never used for naming the first element. Ex. CO is called carbon monoxide, not monocarbon monoxide

Prefixes in Covalent Compounds Number of Atoms Prefix 1 mono- 6 hexa- 2 di- 7 hepta- 3 tri- 8 octa- 4 tetra- 9 nona- 5 penta- 10 deca-

Naming Compounds That Contain Ployatomic Ions You must memorize the names of the polyatomic ions A polyatomic ion consisting of two or more atoms bound together. Oxyanion – A polyatomic ion containing at least one oxygen atom and one or more atoms of at least one other element.

Naming Acids

An acid is defined as a substance that gives off a hydrogen ion (H+) in water. Therefore all acids are made up of a hydrogen cation and either a monatomic or polyatomic anion. Acid names are based on the anion ending.

Rules for Naming Acids If the anion does not contain oxygen, the acid is named with the prefix hydro- and the suffix –ic attached to the root name for the element. Example: Acid – HCl Anion – Cl – Name – hydrochloric acid

Anion ending _____- ide Acid Name hydro-_____-ic + acid

Example H+ + Br- (bromide)  HBr or hydrobromic acid

Rules for Naming Acids When the anion contains oxygen, the acid name is formed from the root name of the central element of the of the anion or the anion name with a suffix of –ic or –ous. When the anion name ends in –ate, the suffix –ic is used. For example: Acid H2SO4 Anion: sulfate Name: Sulfuric Acid

Anion ending _______- ate Acid Name __________- ic + acid

Example H+ + SO42- (sulfate)  H2SO4 or sulfuric acid

Rules for Naming Acids When the anion name ends in –ite, the suffix –ous is used in the acid name For example: Acid – H2SO3 Anion: sulfite Name: Sulfurous acid

Anion ending ________- ite Acid Name _________- ous + acid

Example H+ + NO2- (nitrite)  HNO2 or nitrous acid