1. 2.4 Polar Covalent Bonds 2.4.1. Unequal Sharing
LO: I understand how unequal sharing of electrons affects the atoms bonded together.

2. When the atoms joined by a covalent bond are the same the pull on the shared electrons is .
equal
This is a covalent bond.
pure
If the atoms are different, one might have a stronger pull on the shared than the other.
electrons
This results in the shared electrons being to one atom than the other.
pulled
closer
LO: I understand how unequal sharing of electrons affects the atoms bonded together.

3. The electrons move to the fluorine.
In hydrogen fluoride, the fluorine atom has a pull on the shared electrons.
stronger
The electrons move to the fluorine.
closer
This is shown by an on the bond pointing towards fluorine.
arrow + - H F
Slightly +ve end
Slightly -ve end
A permanent is produced in the molecule.
dipole
The result is a bond.
polar covalent
LO: I understand how unequal sharing of electrons affects the atoms bonded together.

4. Electronegativity
LO: I understand what is meant by electronegativity.

5. Electronegativity is a measure of the attraction an atom has for a of electrons.
shared pair
Electronegativity:
2.2
, across a period.
increases
1.0
2.5
3.5
4.0
1.2
2.2
3.0
2.8
. down a group.
decreases
0.8
2.1
2.6
0.8
LO: I understand what is meant by electronegativity.

6. In a polar covalent bond the atom with the:
Highest electronegativity will be slightly
negative
Lowest electronegativity will be slightly
positive
The greater the difference in electronegativity the more the bond.
polar H Br
will be polar than
more H I
LO: I understand what is meant by electronegativity.

7. Polar Molecules
LO: I understand what is meant by a polar molecule.

8. Polar liquids can be detected by passing a fine stream past a :
A polar molecule is one that has permanent slightly positive and negative sides.
Water is a
polar molecule
Polar liquids can be detected by passing a fine stream past a :
charged rod
Polar liquids will be to the rod.
attracted
Non-polar liquids will flow
straight past
LO: I understand what is meant by a polar molecule.