Bonding Concepts Worksheet - Unit 8/9, Michalek (Page 3 of 30) in pdf

Bonding Concepts Worksheet - Unit 8/9, Michalek Page 3

AP Chemistry - Michalek

Unit 08 Bonding Concepts

8.1 Notes

Bond Energy is the energy required to break a bond. Ionic Bonding is a bonding force that forms a great thermal stability

results from the electrostatic attractions of the closely packed, oppositely charged ions. Ionic compound results when

cations react with anions.

Coulomb’s Law

The energy of interactions between a pair of ions

-19

k = 2.31 x 10

J*nm, E is energy, r is the distance between ion centers, Q

and Q

is the ionic charge.

Example

In solid sodium chloride the distance between the centers is 2.76 A. What is the energy of interaction between the pairs

of ions?

If the sign is negative, the ion pair has a lower energy than the separated ions. This means a bond will form. Chemicals

are most stable in the lowest energy form. This law can also be used to calculate the repulsive energy when two like

charged ions are brought together. A bond will form if the energy of the aggregate is lower than that of the separated

atoms.

Bond length

The system will act to minimize the sum of the positive (repulsive) energy term and the negative (attractive) energy

term. The distance where the energy is at a minimum is called bond length. In covalent bonding the electrons are being

shared by the nuclei. Polar covalent bond share electron unequally; meaning that the electrons are pulled closer to the

most electronegative atom.

Bonding Concepts Worksheet - Unit 8/9, Michalek Page 3