1. Chapter 6B: Chemical Bonding
General Chemistry
Mr. Mata
Cartoon courtesy of NearingZero.net

2. 6-3 Ionic Bonding and Compounds
Ionic Compound- composed of + and - ions combined so charges are equal. (Metal + nonmetal)
Formula Unit- simplest group of atoms form an ionic compound.

3. Cation Formation
Main group metals lose all their valence e-’s to form cations (+):
This loss of electrons is called oxidation.
Na Na e sodium
Mg: Mg e magnesium
: Al . Al e aluminum

4. Anion Formation Non-metals gain e-’s to form anions (-).
This process is called reduction.
Cl chloride (gain 1 e-)
O oxide (gain 2 e-’s)
N nitride (gain 3 e-’s)

5. Ionic Bond - charges are attracted to + charges.
- anions are attracted to + cations.
The result is an ionic bond.
3-D crystal lattice of anions & cations formed.

6. Structure of NaCl

7. Properties of Ionic Compounds
Crystals form.
High melting point & boiling point.
Brittle (breaks easily).
Melt when heated (very high temps!)
Aqueous solutions conduct electricity. (solutions mixed in water)

8. Electronegativity (EN)
Atoms to the right & top of Periodic Table have greater EN values.
F most EN of elements (EN = 4.0).
Fr least EN of elements (EN = O.7).
Cl =3.0 H = 2.1 S = 2.5
O = 3.5 Na = 0.9 Br = 2.8
C = 2.5 N = 3.0 I = 2.5

9. Polar & Nonpolar Bonds
H-H is non-polar because H & H have the same EN’s. (EN diff. = 0)
Cl-Cl is non-polar because Cl & Cl have the same EN’s. (EN diff. = 0)
H-Cl is polar because H & Cl have different EN’s. ( H = 2.1, Cl = 3.0 )

10. Predicting Bond Type
There is a continuum between non-polar covalent bonds to ionic bonds.
Non-polar bond; little difference in EN between atoms. (EN diff. = 0 – 0.3)
Ionic bonds; greatest EN diff between atoms. (ΔEN > 1.7)
Polar covalent bonds; in between EN diff between atoms.
(EN diff. = 0.3 – 1.7)

11. Ionic vs. Covalent Bonds
Sharing e-’s
non-metal + non-metal
Molecular (low mp/bp)
ex: CO2, Cl2
Macromolecular (high mp/bp)
Ex: C(diamond), SiO2
Non conductors
Ionic Bonds
Exchange e-’s
Metal + non-metal
3-D units (crystals)
high mp/bp
Brittle, melt
Ex: NaCl
conduct electricity

12. Ionic Bonding in NaCl

13. Ionic Bonding in NaCl

14. 6-4 Metallic Bonding Metals- conduct heat, have low ionization energy
Low EN; give up electrons easily.
Metals have luster (shine), are malleable (can be hammered into sheets) and are ductile (drawn into wires).

15. Metallic Bonding
Metallic Bonding - type of bonding found in metallic crystals.
3-D lattice of positive ions.
remain fixed in a crystal lattice.
loosely-held valence e-’s move freely throughout the crystal.
The fluid-like movements of valence e-’s make metals good conductors of heat and electricity.

16. Metallic Bonding

17. Metal Alloys
Alloys -metallic substances composed of two or more elements; at least one of these elements is a metal.
Alloys are important because the properties of an alloy are often superior to those of its component elements.

18. Chapter 6 SUTW Prompt
Describe the different properties of ionic bonds and metallic bonds by describing how the electrons interact with each bonding type.
Complete an 8-12 sentence paragraph using the SUTW paragraph format. Hilight using green, yellow, and pink.
Due Date: Monday, October 16, (start of class)