Warm Up 9: Definitions 11-3-17 LT I can explain how covalent molecules create attractive forces between molecules. Q1. Draw the Lewis dot structure, label oxidation number and structural formula for: O and 2 H C and 4 H C and 2 O Q2. What is the correlation between the number of bonds and oxidation numbers?
Warm Up 9: Definitions 11-3-17 LT I can explain how covalent molecules create attractive forces between molecules. Q1. Draw the Lewis dot structure, label oxidation number and structural formula for: O and H C and H C and O Q2. What is the correlations between the number of bonds and oxidation numbers? A2. There is the same number of bonds as the oxidation number.
When people ask. I can define polar bonds. I can explain how covalent molecules create attractive forces between molecules.
Electronegativity: How strongly atoms "want" or "hold" electrons. On periodic Table!!! The bigger the number the more electronegative the atom. Q. What happens to the charge of each atom when atoms of a covalent molecule share electrons unevenly? A. The electrons spend more time around the more electronegative atom. Q. What does this cause? A.Causes one atom to be more negative than the other. This is known as a polar (covalent) bond.
How to determine if bond is polar or not Combine Electronegative numbers and Following table Subtract the Electronegative values Compare the difference to table Practice problems: a) HBr b) CO 2 c) H 2 O 3 min Electronegative difference 0.0-0.4 0.41-1.0 1.01-2.0 Type of Bond Nonpolar covalent Moderately Polar Covalent Very Polar Covalent > 2.00 Ionic
a) HBr b) CO 2 c) H 2 O
Notes 3: Electronegativity & Polar Bonds 3 Attractions Between Molecules Why would there be attractions between molecules? Think about ionic compounds Electrons are never in the same place, but constantly moving. When electrons spend more time around one atom in a molecule there is more of a negative charge there and more of a positive charge on the other atom. This - and + charge attract each other like ionic bonds.
Notes Attractions Between Molecules 1) Dispersion forces: -the weakest molecular attraction forces. -happens in nonpolar covalent bonds -result of electrons always moving, causing an instantaneous - and + end
Notes Attractions Between Molecules 2) Dipole Interactions: -occur in polar Covalent Bonds -one (or more sides) of the molecule is constantly - and other is + -like ionic bonds the - and + charges are attracted to each other
Notes Attractions Between Molecules 3) Hydrogen Bonds: -Only happens with H *remember H has no other electrons around the nucleus -When H is covalently bonded to a very electronegative atom (O, N, F) it also shares electrons of the unshared electrons of ANOTHER molecule. Ex.
Warm Up 9: Definitions 11-3-17 LT I can explain how covalent molecules create attractive forces between molecules. Q1. Draw the Lewis dot structure, label oxidation number, balanced chemical formula, and structural formula for: O and H C and H C and O Q2. What is the correlations between the number of bonds and oxidation numbers? Q3. What makes a covalent bond polar? Q4. Name the three attractions between molecules in order of weakest to strongest.
Warm Up 9: Definitions 11-3-17 LT I can explain how covalent molecules create attractive forces between molecules. Q3. What makes a covalent bond polar? A3. When one atom is more electronegative than the other and they "hug" the electron. Q4. Name three attractions between molecules in order of weakest to most strongest. A4. Dispersion forces, Dipole interactions, Hydrogen Bonds
Notes 3: Electronegativity & Polar Bonds 3 Attractions Between Molecules Why would there be attractions between molecules? Think about ionic compounds Electrons are never in the same place, but constantly moving. When electrons spend more time around one atom in a molecule there is more of a negative charge there and more of a positive charge on the other atom. This - and + charge attract each other like ionic bonds.