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Nomenclature Chapter 4.

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Presentation on theme: "Nomenclature Chapter 4."— Presentation transcript:

1 Nomenclature Chapter 4

2 Nomenclature = Naming Common names were created before there was a system in place More than 4 million chemical compounds, memorizing names would be impossible A system makes it much easier

3 Binary Compounds Compounds composed of 2 elements 2 types
Metal and Nonmetal Two Nonmetals

4 4.1 Naming Compounds That Contain a Metal and a Nonmetal
Remember: When metals and nonmetals combine the compound contains ions Resulting substance is a binary ionic compound Contain cation and anion in that order To name them simply name ions Cation is element name Anion is root of element name with –ide at end NaCl is sodium chloride

5 Certain metal ions form only one cation
Na is always Na+ Cs is always Cs+ Ca is always Ca2+ We will call these Type I cations and they form Type I binary compounds Other metal ions can form more than one cation Cr can form Cr2+ or Cr3+ Lower oxidation number will end in –ous Higher oxidation number will end in -ic We will call these Type II cations and they form Type II binary compounds

6 Type I Binary Ionic Compounds
Cation always named first, anion second When a single element is the cation we simply use its name When a single element is the anion take the root and add –ide Examples NaI is sodium iodide CaO is calcium oxide What would KI be? Potassium iodide What would CsBr be? Cesium bromide Do Practice problems on page 87

7 Type II Binary Ionic Compounds
Need to specify which cation is used Is it Cr2+ or Cr3+? We will use Roman Numerals in name So if it is FeCl2 which Iron is it? Fe2+ (the ferrous ion) or Fe3+ (the ferric ion)? we know Chlorine has a 1- oxidation number so 2 (1-) = 2-, what must Fe be to cancel this out? Fe must be 2+ so it is Fe2+ So name would be Iron II chloride Table 4.2 page 90

8 4.2 Binary Compounds That Contain Only Nonmetals (Type III)
Write first element Write second element Add prefix to 1st element (but not mono-) Add prefix to 2nd element Why do we do this? NO, N2O5, and NO2 would all be nitrogen oxide under the normal rules Instead they are Nitrogen monoxide, Dinitrogen pentoxide, and Nitrogen dioxide one –mono two - di three - tri four - tetra five - penta six - hexa seven - hepta eight - octa nine - nona ten - deca

9 4.3 Review Type I Type II Type III metal and nonmetal
Metal cation has only 1 oxidation number Type II Metal and nonmetal Metal cation has more than 1 oxidation number Tell which ox. # it is with roman numerals Type III Nonmetal and nonmetal Use prefixes to name

10 Naming Binary Compounds

11 4.4 naming Compounds That Contain Polyatomic Ions
FIRST: Copy Table 4.4 on page 100 into notes Polyatomic ion – a charged group of atoms bound together Oxyanion – oxygen and another element Smallest – hypo- Lower - -ite (If only 2, smallest) Higher - - ate (If only 2, largest) Largest – hyper

12 When naming compounds with polyatomic ions follow same rules but anion (second part of formula) is a polyatomic ion just name it

13 4.5 Naming Acids Acid – produces H+ ions (protons) in water
Tastes sour (not a good test) It is like a molecule with a H+ attached to an anion If no oxygen Hydro- in front, -ic at end HCl is Hydrochloric acid If oxygen Root of central element of anion or anion name with –ic or –ous Anion ends in –ate then replace with –ic Anion ends with –ite then replace with -ous

14 4.6 Writing Formulas From Names
You know how to do this

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