4.5 Polarity and Naming Molecular Compounds Objectives 4:d-e, 6:c-e Chemistry

Essential Questions What is the difference between a polar and nonpolar bond? How can you tell if a bond is polar or not? How do you name a covalent/molecular compound?

Types of Covalent Bonds There are two types of covalent bonds: polar and nonpolar The different types exist because atoms do not share electrons equally When electrons are shared equally it is a nonpolar bond When electrons are not shared equally it is a polar bond

Electronegativity What determines if electrons are shared equally? Electronegativity which is the ability to attract electrons in a chemical bond The greater the difference in electronegativity the more polar the bond becomes p 177 has the table of electronegativity

Polar or Nonpolar? (cont) Electronegativity Difference Type of Bond 0-.40 Nonpolar covalent .41-1.99 Polar covalent 2.00 or greater Ionic bond

Polar or Nonpolar? Identify if the following are polar or nonpolar H-H O-H P-Cl F-N Br-I

Polar Bonds In polar bonds the electrons spend more time on the more electronegative element because it is “hogging” the electrons Cl is the more electronegative so the electrons spend more time with it

Polar Bonds What is going to happen to the charges of the atoms in a polar bond? The more electronegative will gain a partial negative charge and the least electronegative will have a partial positive charge The partial charge can be shown with a Greek symbol () delta or special arrows

Polar Bonds (cont) Positive Negative Smaller electroneg # Larger

Naming Covalent Compounds Number Prefix 1 Mono- 2 Di- 3 Tri- 4 Tetra- 5 Penta- 6 Hexa- 7 Hepta- 8 Octa- 9 Nona- 10 Deca- Use prefixes to determine how many of each type of atom Chart is on p 269 If first prefix is mono, leave it off The last element listed ends in -ide

Naming Covalent Compounds (cont) Name the following CO SiO2 N2Se P2O4 SI2 ClF C2H4

Naming Covalent Compounds (cont) Write the formulas for the following: Octacarbon octahydride Diphosphorous trinitride Carbon disulfide Bromine monofluoride

Essential Questions What is the difference between a polar and nonpolar bond? How can you tell if a bond is polar or not? How do you name a covalent/molecular compound?

4.5 Tracked Assignment Worksheet