Chemical BondingChemical BondingChemical BondingChemical BondingWhat is the bond called ifWhat is the bond called if

(a)(a) Electrons are transferred?Electrons are transferred?(b)(b) Electrons are shared equally?Electrons are shared equally?

(c)(c) Electrons are not shared equally?Electrons are not shared equally?

Covalent Bonds

• Are very strong

• Draw Lewis structures for F2, O2, N2

• Which bond is stronger?

Bond Strength

• Depends on (a) Bond length = distance between

the bonds(b) Number of bonds (no. of shared

e)

Polar Covalent Bond

• Electrons not shared equally

• One end of the bond is slightly more negative, and the other end is slightly more positive.

3 Types of Chemical Bond

Examples

• Determine the type of chemical bond for the following using differences in electronegativities (absolute value)

(a) NaCl(b) CH4

(c) F2

Answer

Predict Formula of Covalent Compounds

Criss-cross Valence

Examples

• (a) P and Cl• (b) B and O• (c) C and S• (d) P and O

Shape and Behaviour of Molecules

Lewis structures can be used to help visualize molecules in 3 dimensions.

Since all electrons carry the same charge, it is reasonable to assume that electron pairs in bonds and lone pairs will be oriented in a molecule as far away from each other as possible.

Valence Shell Electron Repulsion Theory (VSEPR)

Draw Lewis Structures for each example and correspond to the VSEPR shapes.