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BONDING TYPES ctnd.
What is covalent bonding?What is metallic bonding?
How do you name or write covalent compounds?
BONDING TYPES
• Ionic stealing, transfer of electrons• Covalent sharing of electrons• Metallic bonds are attractions of floating
valence e- to other positively charged cations (Sea of electrons, drifter)
Watch Video: Common Types of Atomic Bondshttp://aaronfreeman.wikispaces.com/file/view/Common_Types_of_Atomic_Bonds.mov
Ionic or Covalent?
• How can I easily determine if a substance is ionic or covalent?
• By calculating difference in electronegativity! • Rule of Thumb – Magic Number = 1.67• If the difference is > 1.67 IONIC
< 1.67 COVALENT
= 1.67 50% Ionic and 50% Covalent
ELECTRONEGATIVITY VALUES
EXAMPLES• EX. Examine electronegativity between F and Cs
F = 4.0 Cs = .7|4.0 - .7| = 3.3 so …. IONIC COMPOUND
Practice• Ca and Cl Ca = 1.0 Cl = 3.0• Difference is 2.0 so Ionic Compound
• S and O S = 2.5 O = 3.5
• Difference is 1 so Covalent Compound
COVALENT COMPOUNDS • Molecules neutral group of atoms held together
by covalent bonds
• Molecular/Covalent Compounds compound whose simplest units are molecules
• Low melting/boiling points• Made from two nonmetals
• EX. H2O water CO2 carbon monoxide
MOLECULES
MOLECULAR FORMULA
• Molecular Formula chemical formula of covalent cmpd
• Actual number of atoms in each molecule
• Does NOT tell us about arrangement of atoms
• H2O : 2 atoms of H 1
atom of O• C2H6 : 2 atoms of C
6 atoms of H
NAMING MOLECULAR COMPOUNDS
• DO NOT USE CHARGES!!!!
• USE PREFIXES AND SUFFIXES tells how many atoms of each element are present in each molecule of the compound
• How would you name?CO2 or SO3
Carbon Dioxide Sulfur Trioxide
NAMING MOLECULAR COMPOUNDSIf covalent: use prefixes• OMIT the prefix mono- if the first atom is = 1 p.269• ADD suffix to the second element of –ide
• SF6
• Cl2O8
• SO3
• ICl4
• P2O5
• Carbon Tetraiodide• Phosphorus Trichloride• Dinitrogen Trioxide• Br2 I2 O2
Sulfur Hexafluoride
Dichlorine Octoxygen …. NOT Octa-oxygen
Sulfur Trioxide
Iodine Tetrachloride
Diphosphorus Pentoxide … NOT Penta-oxide
CI4
PCl3
N2O3
Bromine Iodine Oxygen