1. Covalent Bonds

2. Why do atoms bond?
Atoms want stability- to achieve a noble gas configuration (octet)
For ionic bonds there is a transfer of electrons to get an octet of electrons
For covalent bonds there is a sharing of electrons to get an octet

4. What is a covalent bond?
Covalent bond - the chemical bond that results from sharing of valence electrons
Occurs with elements close to each other on the periodic table
Between a nonmetal and a nonmetal
Molecule is two or more atoms bonded covalently

5. Examples of Molecules F2 H2O NH3 (ammonia) CH4 (methane)
Notice there are no metals, only non-metals

6. Diatomic Elements (Molecules)
Some elements do not exist as a single atom
Elements that exist as two atoms:
H2, O2, N2, Cl2, Br2, I2, F2
HONClBrIF
Magnificent 7-
don’t forget H

7. Molecules
Diatomic
HCl CO

8. Molecules
Polyatomic O3
H2O
CO2
NH3

9. 3 Types of Covalent Bonds: Single, Double and Triple bonds
3 Pencil Demo
Make as many observations as you can
i.e. facial expressions, body position, muscles used, noises made, force or energy exerted, etc.

10. Strength of Covalent Bond
Several factors control bond strength
Number of shared electrons-the more electrons shared, the shorter the bond,
the greater the bond strength
Size of the atoms

11. Single Covalent Bonds Each atom shares one pair (2 total) of electrons
Longest bond
Weakest bond of the three
H—H
Lewis Structure

12. Double Covalent Bonds O2
Each atom shares two pairs (4 total) of electrons
Medium length bond
Medium strength bond
Label bonding electrons and lone pairs
Lewis Structure O2

13. Triple Covalent Bond
Each atom shares three pairs (6 total) of electrons
The shortest bond
The strongest bond
Carbon and nitrogen can form triple covalent bonds
Lewis Structure N2

14. Covalent Molecule Properties
Tend to be soft solids, liquids, or gases at room temperature
Low melting and boiling points
Poor conductors of heat and electricity
Non-electrolytes – do not conduct electricity in water

15. Sources chemistry.about.com 2012books.lardbucket.org
chemwiki.ucdavis.edu
wps.prenhall.com 
academic.brooklyn.cuny.edu