1. Types of Bonding Objectives: 1. Identify the 3 main types of bonds
2. Identify the main properties of each
3. Be able to distinguish between the types of bonds

2. Chemical Bonding Review
Chemical bonds are attractive forces (electrostatic attractions) which hold atoms together to form compounds
Types of bonds:
Ionic: Metal with a Non-metal
Covalent: Non-metal with a Non-metal
Metallic: Metal with a Metal

3. Chemical Bonding Non-Metal with a Non-Metal
What are the chemical properties of non- metals? (think trends)
What do you think will happen when 2 react together?
There are two possible results:
Equal sharing
Unequal sharing

4. Chemical Bonding Non-Metal with a Non-Metal Non-Polar Covalent Bonding
Two atoms of the same element
Perfect sharing
Non-Polar Covalent
Equal Sharing
Why?
Same e-neg H
2.10 H
2.10

5. Chemical Bonding Non-Metal with a Non-Metal Polar Covalent Bonding
2 non-metals who are close enough in strength (e-neg) that they share
This sharing is unequal
Polar Covalent
Unequal Sharing
Why?
Similar e-neg O
3.44 H
2.10 δ-
Dipole
Negative δ+
Dipole
Positive

6. Chemical Bonding
Some properties of covalent compounds:
Most covalent molecules have lower melting & boiling points, softer
Often insoluble (non-electrolytes, don’t break down in water)

7. Chemical Bonding Some properties of covalent compounds:
7 elements are diatomic: found naturally as molecular elements of two identical atoms
Hydrogen (H2)
Nitrogen (N2)
Oxygen (O2)
Fluorine (F2)
Chlorine (Cl2)
Bromine (Br2)
Iodine (I2)

8. Chemical Bonding
Bonding Continuum – Pulling it all together

9. Chemical Bonding To summarize… Bond Type Formed by Mode of formation
Properties
E-neg difference
Covalent
Nonmetals of similar
e-negs
Sharing of electrons
-no ions
-low m.p.
-insulators
SMALL
Ionic
Metal and nonmetal with widely different e-neg
Electrostatic attraction between ions resulting from transfer of electrons
-charged ions in all phases
-solids insulate
-gases, liquids conduct
-high m.p.
LARGE
Metallic
Atoms of metals
Delocalized electron cloud around atoms of low e-neg (sea of electrons)
-conduct in all phases
-shiney
-very high m.p.

10. Chemical Bonding
La fin!