Covalent

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Covalent Bonding
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Covalent Bond
F2
H
H
H
H
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diatomic elements
Octet Rule
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degree of sharing
e- shared ______________ atoms have very close to
___________ electronega-tivity (EN)
e- shared ____________ ____________ EN difference
one atom _____________from another _________
EN difference
Na
H
H
H
Cl
Cl
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Bond Type
? EN
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Use electronegativities to rank these bonds from
least polar to most polar
H-F C-S C-H Ca-Cl
Rank these bonds from least ionic character to
most
K-I S-O Ba-F I-I
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Molecular Geometry
VSEPR
atoms
shared e- prs.
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Lewis dot structures





Rules for drawing dot structures

• Calculate the number of valence e- each atom
• contributes. Divide this number in half to
  get
• the number of pairs.

ex CBr4
2. Decide which element will be the center atom
usually the one that has fewer atoms or the
lower electronegativity (C, S, P are good bets)

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3. Use pairs of e- (as single covalent bonds) to
attach all the other atoms to the center atom.
ex CBr4
4. Put lone pairs of e- on the outside atoms
until each atom has 8 electrons (4 pairs) or
1 pair on hydrogen.
5. Put any leftover pairs on the center atom so
that it also has 4 prs around it.
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6. If not enough pairs to obey octet rule,
convert lone pairs into additional shared
pairs (double or triple bonding).
7. Decide what shape the molecule should be.
CBr4
Examples
H2O
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NI3
CO2
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COF2
H2S
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Properties due to type of bond
ionic
polar covalent
nonpolar covalent
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ionic
polar
nonpolar
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ionic
polar
nonpolar
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Intermolecular bonding
attractive forces _________________molecules
_____________ than ionic and covalent (within
molecules or crystals)
attractive forces btw. _______________ molecules
ex CO
CO
CO
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like dipole-dipole except must have _____ on a
highly electronegative element
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d
H
H
O
O
d-
d-
d
H
H
d
H
d
d-
O
H
H
H
O
O
H
H
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attractive forces between_________________
_ molecules

Cl
Cl
Cl
Cl
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dispersion forces become _______________as
molecules get ______________________________
Ex F2 Cl2 Br2 I2
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Names Formulas Of covalent Compounds
I. Binary Covalent
Use prefixes to indicate the number of atoms
never use ____________ on the first element
not allowed
oo
ao
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examples
CCl4 SO3 N2O P2O5 CO2
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use common names for
H2O NH3 H2O2

write formulas
sulfur hexafluoride carbon monoxide carbon
disulfide dinitrogen tetroxide
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II. Acids
have H on an anion (-)
a. Binary acids
prefix ____________ stem, ending ________
ex
HCl HF HCN
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write the formula
hydrobromic acid hydrosulfuric acid
b. oxyacids
contain a polyatomic ion
change ______to _______
change ______to _______
HNO3 HNO2
H2SO4 H2SO3
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Write the formula acetic acid chlorous
acid phosphoric acid phosphorous acid