Chapter 6.1 Introduction to Chemical Bonding

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Chapter 6.1 Introduction to Chemical Bonding

• Molecule smallest electrically neutral unit of
  a substance that still has the properties of the
  substance
• Made up of two or more atoms

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Molecular Compound

• Compounds composed of molecules made up of
  different atoms

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Molecular Compounds

• Usually low melting and boiling points
• Usually liquids or gases at room temperature
• Usually made up of two or more nonmetals

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Ions

• Atoms or groups of atoms that have a positive or
  negative charge
• Forms when an electron is lost or gained

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Cation

• Any atom or group of atoms that has a positive
  charge
• Lose electrons
• Usually Metals

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Anion

• Any atom or group of atoms that has a negative
  charge
• Gains electrons
• Usually Nonmetals

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Ionic Compounds

• Compound composed of anions and cations
• Usually a metal cation and a nonmetal anion

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Characteristic Molecular Compound Ionic Compound
Representative Unit Molecule Formula Unit
Type of Elements Nonmetals Metal and Nonmetal
Physical State Solid, Liquid or Gas Solid
Melting Point Low below 300 degrees Celsius High above 300 degrees Celsius
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Chapter 6.2 Representing Chemical Compounds

• Chemical Formulas
• Molecular Formulas
• Formula Units
• Laws of Proportions

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Chemical Formulas

• Show the kinds and numbers of atoms in the
  smallest representative unit of the substance

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Monatomic

• Represent their chemical formula by writing their
  symbol
• Copper Cu
• Helium - He

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Diatomic

• If the molecules of an element have more than one
  atom, use a subscript to indicate how many
• Hydrogen H2
• Oxygen O2

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The Seven Diatomic Elements You must Memorize

• Hydrogen H2
• Fluorine F2
• Oxygen O2
• Nitrogen N2
• Chlorine Cl2
• Bromine Br2
• Iodine - I2

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Molecular Formulas

• Shows the kinds and numbers of atoms present in a
  molecule of a compound
• Does not show anything about the structure

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Ammonia
NH3
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Formula Units (Ionic Compounds)

• Does not represent a molecule
• No separate molecular units
• Arranged in an orderly pattern

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Formula Unit

• Lowest whole number ratio of ions in a compound
• NaCl 11
• MgCl2 12

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The Law of Definite Proportions

• In samples of any chemical compound, the masses
  of the elements are always in the same proportion.

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The Law of Multiple Proportions

• Whenever two elements form more than one
  compound, the different masses of one element
  that combine with the same mass of the other
  elements are in small whole number ratios.

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Chapter 6.3 Ionic Charges

• Monatomic Ions
• Polyatomic Ions

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Monatomic Ions

• Ions consisting of only one atom

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Monatomic Ions Cations

• Group 1A ions all have a 1 charge
• Group 2A ions all have a 2 charge
• Group 3A ions all have a 3 charge
• Only for metals

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Monatomic Ions Cations

• ? the group number from 8 to get number of the
  charge

Cross this out!
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Monatomic Ions - Anions

• Group 7A ions all have a 1 charge
• Group 6A ions all have a 2 charge
• Group 5A ions all have a 3 charge
• Only for nonmetals

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Monatomic Ions - Anions

• Subtract group number from 8 to get number of the
  charge

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Naming ions with more than one oxidation numbers

• Stock System
• Use a roman numeral after the symbol to indicate
  charge
• Iron
• Fe2 - Iron (II) ion
• Fe3 - Iron (III) ion

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Polyatomic Ions

• Tightly bonded group of atoms that behave as a
  unit and carry a charge
• Sulfate SO42-

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Polyatomic Ions

• Most end in ite or ate
• Look at table E
• Three exceptions
• Ammonium
• Cyanide
• Hydroxide

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Polyatomic Ions

• ite indicates one less of oxygen
• ate indicates one more of oxygen
• Does not tell how many oxygens

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Chapter 6.4 Ionic Compounds

• Writing Formulas
• Naming Binary Compounds
• Ternary Ionic Compounds

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Anions

• Change ending to ide
• Oxygen Oxide
• Sulfur - Sulfide

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Writing Formulas for Binary Ionic Compounds

• Binary Compound composed of two elements
• The positive charge of the cation must balance
  the negative charge of the anion.

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Writing Formulas for Binary Ionic Compounds

• The total net charge must equal 0.
• Potassium Chloride
• K and Cl-
• KCl
• Rust - Iron(III) Oxide
• Ions - ?
• Formula ?

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Crisscross method

• Rust Iron(III) Oxide
• Fe3 and O2-

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Naming Binary Ionic Compounds

• Cation first, anion second
• Make sure charges balance, if not, use subscripts
  to balance
• If the cation has more than one oxidation number,
  use roman numerals to indicate charge (ONLY
  Positive)

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Ternary Ionic Compounds

• Contains atoms of three different elements
• Calcium Carbonate
• CaCO3

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Ternary Ionic Compounds

• ate or ite ending indicates a polyatomic
  anion containing oxygen
• Calcium Nitrate
• Ca2 , NO3-
• Ca (NO3)2

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Chapter 6.5 Molecular Compounds and Acids

• Binary Molecular Compounds
• Naming Common Acids

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Binary Molecular Compounds

• Composed of two nonmetallic elements
• Prefixes are used to indicate the number of each
  atom present

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Binary Molecular Compounds
Prefix Number
Mono- 1
Di- 2
Tri- 3
Tetra- 4
Penta- 5
Hexa- 6
Hepta- 7
Octa- 8
Nona- 9
Deca- 10

• Prefixes

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Binary Molecular Compounds

• All end with ide
• Drop the vowel at the end of the prefix if the
  element begins with a vowel
• CO
• Carbon Monooxide
• Carbon Monoxide

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Binary Molecular Compounds

• If the first element has just one atom, drop the
  mono-
• CO
• Monocarbon monoxide
• Carbon monoxide

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Binary Molecular Compounds

• Tetraiodine nonoxide
• ??
• N20
• ??

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Naming Common Acids

• Compounds that produce hydrogen ions when
  dissolved in water
• Anions connected to as many H ions to make the
  molecule neutral

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Naming Common Acids

• HCl
• Hydrochloric Acid
• H2SO4
• Sulfuric Acid
• HNO3
• Nitric Acid
• HC2H3O2
• Acetic Acid
• H3PO4
• Phosphoric Acid
• H2CO3
• Carbonic Acid

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Chapter 6.6 Summary of Writing and Naming
PxQy
P Hydrogen
P Hydrogen
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