The chemical formula represents the composition of each molecule.

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NAMING COMPOUNDS

• The chemical formula represents the composition
  of each molecule.
• In writing the chemical formula, in almost all
  cases the element farthest to the left of the
  periodic table is written first because it is the
  least electronegative.

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NAMING COMPOUNDS

• So for example the chemical formula of a compound
  that contains one sulfur atom and six fluorine
  atoms is SF6.
• If the two elements are in the same Group or
  Family, the symbol of the element of that is
  lower in the group (i.e. heavier lower
  electronegativity) is written first e.g. IF3.

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Naming Covalent Compounds

• In naming covalent compounds, the name of the
  first element in the formula is unchanged.
• The suffix -ide is added to the second
  element.
• Often a prefix on the name of the second element
  indicates the number of the element in the
  compound
• SF6 sulfur hexafluoride
• P4O10 tetraphosphorous decoxide
• CO carbon monoxide
• CO2 carbon dioxide

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Naming Covalent Compounds Cont.

• SF6 sulfur hexafluoride
• P4O10 tetraphosphorous decoxide
• CO carbon monoxide
• CO2 carbon dioxide
• Notice that the first element does NOT get a
  mono- prefix!

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Hydrogen Cmpds

• The binary compounds of hydrogen are special
  cases. They were discovered before a convention
  was adopted and hence their original names have
  stayed
• Water H2O is not called dihydrogen monoxide
• Hydrogen forms binary compounds with almost all
  non-metals except the noble gases.

• Example
• HF - hydrogen fluoride
• HCl - hydrogen chloride
• H2S - hydrogen sulfide

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Organic Nomenclature

• The molecular formulas for compounds containing C
  and H (called hydrocarbons) are written with C
  first.
• Example, CH4, C2H6, etc.

• Organic molecules (containing C) have a separate
  nomenclature

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BINARY IONIC COMPOUNDS

• Compounds formed by elements on opposite sides of
  the periodic table which either give up (left
  side metals) or take up electrons (right side
  nonmetals).
• Depending on the atom, there can be an exchange
  of more than one electron resulting in charges
  greater than 1.

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• Group IA alkali metals loose 1 e- to form 1
  (Na)
• Group II A alkaline earth metals loose 2 e- to
  form 2 (Ca2)
• Group III A loose three e- to form 3 (Al3)
• Group IV A loose four e- to form 4 (Sn4)
• Group V A accept three e- to form 3 (N-3)
• Group VI A accept two e- to form 2 (O-2)
• Group VIIA accept one e- to form 1 (Cl-1)

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Naming BINARY IONIC compounds

• Cations
• For Na, Ca2, the name of the ion is the same
  except refer to the ion.
• So SODIUM ION or SODIUM CATION
• Anions suffix ide
• So Cl- is chloride, Oxygen O2- is OXIDE S2- is
  SULFIDE
• NaCl - sodium chloride
• CaCl2 - calcium chloride

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Naming BINARY IONIC compounds

• EXAMPLES CONT.

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Covalent, charged compounds - MOLECULAR IONS

• Negative Molecular Ions

• Positive Molecular Ions
• End the name with ium or onium
• NH4 is ammonium, H3O is hydronium

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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.

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• 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
• An older scheme differentiated between the lower
  and higher charge by ending the name of the
  element with ous to indicate the lower charge
  and ic for the higher.
• ferrous chloride gt FeCl2
• ferric chloride gt FeCl3
• However, this convention does not indicate the
  numerical value of the charge.

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TERTIARY IONIC COMPOUNDS

• NAME THE METAL NORMALLY, WITH A ROMAN NUMERAL IF
  NEEDED FOR A TRANSITION METAL
• NAME THE APROPRIATE POLYATOMIC ION

Au2(Cr2O7)3 Sc4(P2O7)3 Mg (SCN)2 V3(BO3)5
Gold (III) Dichromate Scandium
Pyrophosphate Magnesium Thiocyanate Vanadium (V)
Borate
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Summary of Naming Compounds
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NAMING ACIDS

• An acid can be defined as a substance that yields
  hydrogen ions (H) when dissolved in water.
• EXAMPLE HCl
• Pure substance, hydrogen chloride
• Dissolved in water (H Cl-), hydrochloric acid
• An oxoacid is an acid that contains hydrogen,
  oxygen, and another element.

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Naming Acids Cont.
Name of ion Name of Acid
Sulfate (SO4)-2 Sulfuric Acid H2SO4
Sulfite (SO3)-2 Sulfurous Acid H2SO3
Hyposulfite (SO2)-2 Doesnt exist!
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Representing Formulas of Covalent Ionic Bonds
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Formula Types

• An empirical formula shows the simplest
  whole-number ratio of the atoms in a substance

• A molecular formula shows the exact number of
  atoms of each element in the smallest unit of a
  substance

empirical
molecular
H2O
H2O
CH2O
C6H12O6
O
O3
N2H4
NH2
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