Bonds as a Continuum

1
Bonds as a Continuum

• Electronegativity

2
Polar Bonding

• When identical atoms are covalently bonded
  together, the electrons are shared equally
  between them.

3
Polarity on Different Atoms

• When different atoms are covalently bonded
  together though, the electrons are not shared
  equally. One atom will have a stronger attraction
  for the shared pair of electrons.
• Example HCl (on next slide)

4
HCl

• In HCl, the Chlorine attracts the electron pair
  more than the hydrogen.
• The electrons will stay closer to the chlorine
  making the chlorine more negative than the
  hydrogen atom.
• However, the whole molecule overall is still
  neutral.

5
Electronegativity

• Fundamentally bonds form because the positive
  nucleus is attracted to the negative electrons.
  However, some atoms are more attracted to some
  atoms than others. This property is known as
  electronegativity.
• Electronegativity the extent to which atoms of
  some elements attract the shared electrons to a
  much greater extent than do atoms of other
  elements.

6
Electronegativity increases to the top right of
the periodic table.
7
Bond Type and Electronegativity
8
Non Polar Covalent

• The atoms in this covalent molecule are sharing
  the electrons equally or very nearly to equal.
  Neither atom is drastically more negative than
  the other.
• Has electronegativity
• less than 0.5
• Example

9
Polar Covalent

• A bond in which the electrons are shared
  unequally between the atoms. One atom tends to be
  more negative than the others.
• Electronegativity between 0.5 and 2.1
• Example

10
Ionic Bonding

• Ionic Bonding has an electronegativity so strong
  that one atom is purely negative and one atom is
  purely positive.
• Electronegativity must be 2.1 and greater.

11
(No Transcript)
12
Example Problem

• Classify the type of bonding using
  electronegativity
• CaO
• Calcium EN 1.0
• Oxygen EN 3.5
• Subtract 3.5 -1.0 2.5 (ionic bond)
• We also know it is ionic because it is one metal
  and one non-metal.