1. Covalent Bonds
Chapter 1 Section 3

2. Background Ionic bonds usually form between a metal and a nonmetal.
But when 2 nonmetals bond, a lot of energy is needed to either gain or lose an electron.
Instead of using energy, atoms of nonmetals will SHARE their electrons in order to bond.

3. Covalent Bonds
Covalent Bond – forms when 2 or more nonmetal atoms share electrons.
By sharing, each atom has a full outer energy level.

4. Here is an animation showing sharing electrons.

6. When two or more atoms are joined in a covalent bond, they make a Molecule.
Examples:
A hydrogen molecule is composed of 2 covalently bonded H atoms.

7. A water molecule is composed of 1 oxygen and 2 hydrogen atoms bonded together.

8. Diatomic Molecules
Often in nature, covalent bonds occur between the same element
The following molecules are found in nature as diatomic molecules:
H O N Cl I Br F

9. Other Single Covalent Bonds – Cl2
Or written:

10. Double Covalent Bond – two pairs of e- shared

11. Triple Covalent Bond – three pairs of e- shared…whoa.

12. Making Covalent Bonds…is fun
Draw Lewis Dot Diagrams
Count # of unpaired electrons on each
Share unpaired electrons so all are happy
Draw using dashes for bonds
Write formula
Bathe in the success of completing a covalent bond problem

13. Metallic Bonding
Bond formed by the attraction between positively charged metal ions and the electrons around them (the sea of electrons)
Occurs in metals …duh

15. Characteristics of Metals
Conduction – electrons can flow easily through them (conduct electricity)
Ductility – ability to be made into wires
Malleability – ability to be hammered into sheets
In general, metals may be reshaped or bent without breaking.

18. Single, Double, and Triple Covalent Bonds

19. Other Single Covalent Bonds – Cl2
Or written:

20. Double Covalent Bond – two pairs of e- shared

21. Triple Covalent Bond – three pairs of e- shared…whoa.

22. Naming Covalent Compounds
Element in “leftmost” column goes 1st
*If both elements are in same column, then lower atomic # goes 1st
2. The 2nd element ends in -ide
3. Greek prefixes are used to show the number of each element

23. Greek Prefixes Number Prefix 1 mono- 2 di- 3 tri- 4 tetra- 5 penta-
** SEE PAGE 33 Exception: Mono- is usually dropped on the 1st element

24. Examples
CCl4 = carbon tetrachloride P2O5 = diphosphorous pentoxide CO = carbon monoxide SO2 = sulfur dioxide

25. Some compounds have common names that were made up before this system:
water - H2O
ammonia - NH3
methane - CH4
ethane - C2H6
propane - C3H8