Molecular Formula: shows numbers of atoms

1

• Molecular Formula shows numbers of atoms
• Empirical Formula shows ratio of atoms
• Structural Formula shows location of atoms

2

• Lithium sulfate

Li2SO4
3

• Carbonic acid

H2CO3
4

• Hydrobromic acid

HBr
5

• Bromous acid

HBrO2
6

• Manganese (IV) oxide

MnO2
7

• Carbon tetrabromide

CBr4
8

• Oxygen difluoride

OF2
9

• Dinitrogen tetroxide

N2O2
10

• Hydroselenic acid

H2Se
11

• Barium phosphate

Ba3(PO4)2
12

• Nitric acid

HNO3
13

• Phosphoric acid

H3PO4
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• If a compound starts with a metal, NH4(?), or
  H3O(?), what kind of compound is it?

Ionic
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• If a compound starts with an H, what kind of
  compound is it?

acid
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• If a compound starts with any other nonmetal,
  what kind of compound is it?

Molecule covalent bonds
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Molecular Geometry

• Put 2 bonds in the atom so they are as far
  apart as possible.
• Use a protractor to measure the bond angle.

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Molecular Geometry

• Put 3 bonds in so they are as far apart as
  possible.
• Measure the bond angles.

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Molecular Geometry

• Put 4 bonds in so they are as far apart as
  possible.
• Measure the bond angles.

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VSEPR (Valence Shell Electron Pair Repulsion)

• Pairs of molecular valence electrons stay as far
  away from other pairs as possible

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Bond Angle

• the angle between 2 adjacent bonds.

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Linear

• Bonded atoms form a straight line
• Bond angles 180

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Trigonal Planar

• the bonded atoms form a triangle.
• Bond angles 120

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Tetrahedral

• shape around central atom that has 4 single
  bonds.
• Bond angles 109.5

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Pyramidal

• Central atom has 3 single bonds and one unshared
  pair of electrons.
• Bond angles
  107.3

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Bent

• Central atom has two single bonds and two
  unshared pairs of electrons.
• Bond angles
  104.5

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Bond angles ?

• HCN
• AsI3
• H2Te

• PF3
• CBr4

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Hybrid Orbitals

• Orbitals of bonded valence electrons containing a
  combination of properties of the original
  orbitals.

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• sp hybrid orbital from an s and a p orbital
• sp2 hybrid orbital from 1 s and 2 p orbitals
• sp3 hybrid orbital from 1 s and 3 p orbitals

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Shapes bond angles?

• CCl4
• HCN
• BF3
• BeCl2
• H2S

• NF3
• PCl3
• OF2
• SiO2
• CF4

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Two types of covalent bonds

• polar covalent bond
• nonpolar covalent bond

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Polar covalent bonds

• unequal sharing of e-s
• results in partial charges
• occur between atoms of differing
  electronegativities

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Polar covalent bond
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Types of bonds

• Two O-H bonds

3.44 -2.20 1.24
two polarcovalent bonds
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Nonpolar covalent bonds

• equal sharing of e-s
• no partial charges
• electronegativity differences are 0.4

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Electronegativity differences

• Ionic bonds 1.7
• Polar covalent bonds between 0.4 and 1.7
• Nonpolar covalent bonds 0.4

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Electronegativity (p.169)
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Electronegativity
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Determine Bond Types for

• C-H
• N-H
• O-Cl

• H-O
• K-F
• Na-F

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Dipole

• An unsymmetrical distribution of positive and
  negative charge within a molecule

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Polar bonds, polar molecule
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Polar bonds, nonpolar molecule
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(No Transcript)
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• For a molecule to be polar, at least one bond
  must be polar.

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• If there is no dipole (symmetrical), the molecule
  is not polar
• If there is a dipole (unsymmetrical), the
  molecule is polar