Topics:  Hybridization, s and p bonds.

Read Sections 7.10 - 7.12 (We will not do Sections 13 - 15 in General Chemistry)
Do Problems 20, 21, 22, 23, 24, 25, 34, 84, 86, 88, 90

G. How are atoms "glued" together in a molecule?  Valence Bond Theory.

1. If you are asked to describe to describe the bonding in a molecule such as methane,
a. First draw the Lewis structure and determine the hybridization for each atom in the molecule.
b. Sketch the orbital diagram for the center atom and draw the energy diagram for the valence electrons.  This drawing is for an unhybridized atom.
c. Next sketch the orbital diagram and draw the energy diagram for the valence electrons showing hybridization of the atomic orbitals.
d. Show (using a sketch) how the hybridized orbitals of two elements overlap to form s and p bonds "sigma" or "pi" bond.  Clearly show (using arrows) the shared electrons in the bond.
e. For a given Lewis structure of a molecule, count the number of s and p bonds.

a.  Draw the Lewis Structure and determine its ABE formula.  Draw the best Lewis structure.
b.  Determine the number of lone and bonding pairs of electrons.
c.  What is the shape (linear, octahedral, bent, etc.)?  Sketch the shape or geometry.
d.  What are all the bond angles?
e.  Is the molecule paramagnetic or diamagnetic?
f.  Indicate the polarity of the covalent bonds using a d+ and d-
g.  indicate the direction and size of the dipole moment "arrow".
h.  Is the molecule polar or nonpolar?
i.  What is the hybridization about each atom?
j.  What is the formal charge of each atom.
k.  How many p-bonds? s-bonds?
l.  If there are resonance forms, draw all of them.

Draw the Lewis dot structures of the following molecules and ions:

(a) NO2^-
(b) SF4
(c) XeO4
(d) ClF3
(e) ICl2^-
(f) SF5^-
(g) PCl6^-
(h) AsO3^-
(i) OCN^-  (C is central)
(j) NO2
(k) CO3^2-
(l) PF5

2.  Which have five structural groups (lone pairs, bonding pairs, and/or unpaired electrons) on the central atom?  Give their structural names.

3.  Which have six structural groups (lone pairs, bonding pairs, and/or unpaired electrons) on the central atom?  Give their structural names.

4.  Which have p bonds?  Give the number of s and p bonds for these.

5.  Which have sp² hybridization?

6.  Which feature 120^o and 90^o angles?

7.  Which have d²sp³ hybridization?

8.  Which have formal charges other than zero?

XeO₄ AB₄ tetrahedral

ClF₃ AB₃E₂ T-shaped

ICl₂^- AB₂E₃ linear

SF₅^- AB₅E square pyramid

PCl₆^- AB₆ octahedral

AsO₃^- AB₃ trigonal plane

OCN^- AB₂ linear

NO₂ AB₂E bent (unpaired electron = paramagnetic!)

CO₃^-2  AB₃ trigonal plane

PF₅ AB₅ trigonal bipyramid

1.   XeO₄  PF₅

2.   SF₄ (see saw) ClF₃ (T-shaped)    ICl₂^- (linear)     PF₅ (trigonal bipyramid)

3.   SF₅^- (square pyramid)  PCl₆^-(octahedral)

4.   NO₂^-(2 s, 1p)   OCN^- (2 s, 2p)    NO₂ (2 s, 1p)    CO₃^-2 (3 s, 1p)  AsO₃^- (3 s, 1p)

5.   AsO₃^-  NO₂^- NO₂ CO₃^-2

6.   SF₄  ClF₃  ICl₂^-  PF₅

7.   SF₅^-   PCl₆^-

8.   NO₂^- XeO₄ ICl₂^- SF₅^- PCl₆^- AsO₃^- OCN- NO₂ CO₃^-2