1. Ionic Bonds

2. Chemical Bond
A chemical bond is a force that holds atoms or ions together in a compound
Bonds form so that ions can become STABLE

3. Ionic Bonds in Detail
When atoms form an ionic bond, their electrons are transferred (lost or gained) to the other atom
You need a :
Metal and a nonmetal
Positive Ion and a Negative Ion
Cation and an Anion
The overall # of protons & electrons of the combined atoms remains equal and unchanged therefore, the compound is neutral!

4. Crystals
Crystals are solids whose particles are arranged in a lattice structure
Ionic compounds have a crystalline structure.

5. Properties of Ionic Compounds
Solids
High melting/boiling points
Good conductors of electric current when melted
Often shatter when struck w/ hammer due to very strong bonds

6. Number of Valence electrons Gain / Lose electrons to become stable
Group number
Number of Valence electrons
Gain / Lose electrons to become stable
Ion Charge/ Oxidation Number
Group 1 Metals 1
Lose 1 1+
Group 2 Metals 2
Loses 2 2+
Group 13 3
Lose 3 3+
Group 14 4
Lose or Gain 4
4+ or 4-
Group 15 5
Gain 3 3-
Group 16 Nonmetals
6 valence electrons
Gains 2 2-
Group 17 Nonmetals
7 valence electrons
Gains 1 1-

7. There are 3 kinds of chemical bonds!
Ionic Bonds– force of attraction b/w opposite charges of ions (the transfer of electrons)
Covalent Bonds – force of attraction between negative charges of ions (the SHARING of electrons)
Metallic Bonds – force of attraction between positive charges of ions (a “SEA OF ELECTRONS”

8. Octet Rule
In forming compounds, atoms tend to achieve electron configurations of a noble gas
They either gain to 8 or lose to 0 (so that the outer energy level “drops” and their inner level is stable with 8)

9. Chemical Formula
Chemical Formula – tells what elements a compound contains and the exact number of the atoms of each element
Ex: H2O – 2 hydrogen and 1 oxygen
The 2 is a subscript (written below)
it tells us how many atoms of that
element are in that compound
* If there is no subscript, it is
assumed there is only 1 unit

10. Drawing Ionic Bonds Practice
For each set of elements, draw an ionic bond using Lewis Structures or Bohr Diagrams (You must draw 3 Lewis and 3 Bohr diagrams!):
K + Cl
Ca + O
Li + Br (this one MUST be a Lewis Structure)
Mg + Cl
Na + S
Li + F

11. Covalent Bonds

12. Covalent Bonds in Detail
The neutral particle that forms as a result of electron sharing is called a molecule.
Single covalent bond – made up of 2 shared electrons

13. Double/Triple bonds
Double bond- forms when 2 pairs of electrons are shared
Triple bond- forms when 3 pairs of electrons are shared

14. Covalent Bond Examples

15. Polar and Nonpolar Molecules
Polar molecule – has a slightly positive end & a slightly negative end.
Ex: H2O
Nonpolar molecule – all electrons are shared equally in bonds.
Ex: CCl4

16. Ionic
Covalent
Structure
Network of ions (crystal lattice)
molecules
Valence electrons
transferred
shared
Electrical conductivity
Good (when melted or dissolved)
poor
State at room temp
solid
Solid/liquid/gas
Melt/boiling pt.
Generally high
Generally low