1. 10/26 Opener
Create a cohesive hypothesis from yesterday’s class notes. Be sure to include a rationale for your hypothesis (why). I will ask 5 people to share.
Compare the reaction of sodium & water to sodium & chlorine gas. Why are the reactions so violent, but the products are stable? (Some you can eat!)
3rd Period
Full shells
Stability
Ionization energy (Na)
H energy
Valence shell full
4th Period
Stability
Full valence shell
Unstable stable
Product non reactive

2. Ionic and Covalent Bonds
S WBAT:
Describe the formation of ionic & covalent compounds
Describe the properties of ionic & covalent compounds

3. Formation of Ionic Compounds
Ionic compounds are composed of cations and anions, usually a metal cation and nonmetal anion.
Are electrically neutral

4. Ionic Bonds
Electrostatic forces that hold ions together in ionic compounds are called ionic bonds
Example: Sodium chloride has Na+1 and Cl Their opposite charges attract each other and they “stick together”

5. Formula Units
A chemical formula shows the kinds of elements and the number of each in a compound
Example: NaCl, AlBr3, H2O
A formula unit is the lowest whole-number ratio of ions in an ionic compound
Example: 1:1, 1:3, 2:1
AlBr3
H2O
NaCl

6. Properties of Ionic Compounds
Crystalline Solids (at room temp)
High Melting Point
Conduct an electric current when melted or dissolved in water
Made up of a metal and non metal
Generally a brittle solid
Most ionic compounds are crystalline solids at room temperature
They have a regular repeating 3-D patterns
Ionic compounds generally have high melting points

8. Octet Rule in Covalent Bonding
When bonding an atom either gains or loses electrons to achieve the electron configuration of a noble gas
In covalent bonding, atoms share electrons to attain the electron configuration of a noble gas

9. Properties of Covalent Compounds
Generally insoluble in water
Non conductive
Can be solid, liquid, or gas
Made up of non metals

10. Single Covalent Bonds
Two atoms are held together by sharing a pair of electrons
An electron dot structure represents the shared pair of electrons of the covalent bond by two dots.
Ex: H:H

11. O H F – F Single Covalent Bonds
A structural formula represents the covalent bonds by dashes and shows the arrangement of covalently bonded atoms.
An unshared pair, or lone pair, is a pair of valence electrons that are not shared between atoms
Examples: O H
F – F

12. Double and Triple Covalent Bonds
A double covalent bond involves two shared pair of electrons
A triple covalent bond is formed by sharing three pairs of electrons
Examples:
:N N:
O = C = O

13. Coordinate Covalent Bonds
A coordinate covalent bond is a bond where one atom contributes both bonding electrons
Examples: :C O:
A polyatomic ion, like NH4+ , is a group of atoms with a positive or negative charge that behaves as a unit.

14. Resonance
A resonance structure occurs when it is possible to draw two or more valid electron dot structures that have the same number of electron pairs in the molecule

15. Exceptions to the Octet Rule
NO2 has a single unpaired electron on the N
Phosphorus and sulfur can have 10 or 12 valence electrons sometimes

16. As a class What is an atom trying to do when it bonds?
What is the difference between an ionic bond and a covalent bond
What is an electron dot structure?
If two atoms are bonded together, how do you show their dot structure?