Chemical Bonds

1
Chemical Bonds

• Chapter 20

2
Sec. 1 - Combined Elements

• Elements make ? compounds
• Properties of compounds are different from
  elements
• Ex Sodium Chloride, NaCl (table salt)
• Na silver, metal, reacts violently w/ H2O
• Cl poisonous greenish-yellow gas

3
Chemical Formulas

• H2O ? 2 atoms H and 1 atom O

4
Atomic Stability

• Why do atoms form compounds?
• To be stable
• Why dont noble gases form compounds?
• Stable! ? Full energy levels!!
• All atoms form compounds to get FULL ENERGY
  LEVELS ? stable

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Atomic Stability
6
Atomic Stability

• 1st energy level full with 2 e-
• Other levels full with 8 e-

7
Stability is Reached

• NaCl is made from atoms losing or gaining
  electrons
• H2O is different ? elements share electrons
• Both ways make a
• Chemical Bond force that holds atoms together in
  a compound

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Types of Bonds

• Section 2

9
Ionic Bonds

• Atoms can lose or gain e- to make an ion
• Ion a charged particle because it now has either
  more or fewer e- than p
• charge if fewer e- than p
• - charge if more e- than p

10
Calcium Oxide - CaO

• Calcium has 2 valence e-
• Loses 2 e- and becomes an ion
• Ca2
• Oxygen has 6 valence e-
• Gains 2 e- and becomes an ion
• O-2
• Calcium gives e- to Oxygen
• Opposite charges ATTRACT!!

11
Ionic Bond Metal and Nonmetal

• Def the force of attraction between opposite
  charges of the ions
• Ex MgCl2 zero net charge
• Smallest Particle formula unit

12
Covalent Bond 2 Nonmetals

• Def attraction between atoms when they share
  electrons
• Smallest particle molecule
• H2O
• CO2
• N2

13
Covalent Bonds

• Single Covalent Bond 2 shared electrons
• Multiple Bonds
• Double (4 shared e-)
• Triple (6 shared e-)

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Naming Compounds

• Section 3

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Naming Ionic Compounds

• Binary compound has 2 elements
• Ionic compounds name of ions makes name of
  compound
• Positive Ions name of element
• Na Sodium ion
• Negative ions end in ide
• Cl- Chloride ion

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Special Ions
17
Polyatomic Ions
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Sec. 3 Writing Formulas

• Remember compounds are NEUTRAL!!
• Write the () ion
• Write the (-) ion
• Balance charges criss-cross method
• Reduce to smallest whole s

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Write the Formula

• Lithium Nitride
• Lead(IV) Phosphide
• Calcium Fluoride
• Ammonium Phosphate
• Magnesium Hydroxide

20
Naming Ionic Compounds

• Put the two ion names together!
• NaCl
• Na Sodium ion
• Cl- Chloride ion
• Sodium Chloride

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Practice Naming

• RbCl
• Mg3N2
• AlF3
• CrCl3
• Ca(OH)2
• Na2CO3
• NH4Cl

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Naming Covalent Compounds

• No ions involved
• Same elements can make different compounds CO,
  CO2
• Naming Use prefixes to tell how many atoms of
  each element
• Second element ends in -ide
• Prefix mono is left out with the first element

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Prefixes
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Practice Naming

• N4O6
• C2O5
• PH3
• Sulfur Hexafluoride
• Dihydrogen Monoxide

25
Hydrates

• Def has water chemically attached to its ions
• CoCl2 6H2O
• Cobalt Chloride Hexahydrate
• CaSO4 2H2O
• Calcium Sulfate Dihydrate