1. Bonding: Ionic vs. Covalent
Honors Coordinated Science II
Wheatley-Heckman

2. What is a Chemical Bond?
The interaction between electrons of different atoms.
The electron cloud of an atom reacts to any electric charge, not just that of its own nucleus.
Can react to the positive charge of another atom’s nucleus.
There are different kinds of interactions between atoms depending on the elements.

3. Ionic Bonds
Happen when one or more electrons are transferred between atoms.
Causes one atom to become positive, and one to become negative.
The oppositely charged ions are now attracted to each other.
Occurs between a metal and non-metal.

4. Ionic Bond Example:

5. Covalent Bonds
When electrons are shared between atoms to fill the outer shell of each.
As 2 atoms approach each other, each nucleus begins to tug on the other’s electrons. Eventually, the orbitals overlap, forming a covalent bond.
Occurs between 2 non-metals.

6. Covalent Bond Example:

7. Covalent Bonds
Sometimes, electrons are shared equally, but sometimes one atom “hogs” the electrons.
When electrons are NOT shared equally, we say the bond is polar covalent. If electrons are shared equally, the bond is non-polar covalent.

8. Electronegativity Difference
Determining Polarity
Electronegativity and ionization energy determine polarity.
Bond Type
Electronegativity Difference
Non-polar covalent
Less than 0.5
Polar covalent
Between
Ionic
Greater than 2.1

10. Ionic and Covalent Bonding

11. Valence Electrons and Bonding Patterns
Only unpaired valence electrons bond.
In a molecular compound, each unpaired electron can form one covalent bond.

12. Learning Check Which electrons are involved in bonding?
What is the difference between ionic and covalent bonds?
What determines polarity?
Hydrogen and Carbon bond together. What kind of bond is this?
Sodium and Fluorine bond together. What kind of bond is this?
How many bonds does Potassium make?
How many bonds does Aluminum make?
How many bonds does Sulfur make?
How many bonds does Neon make?