1. Covalent Compounds
January 2015

4. Covalent Compounds
Covalent Bond – chemical bond that results from sharing electrons
Molecule – formed when two or more atoms are bonded covalently

5. Naming Binary Compounds
First element named first
Second elements ending is changed to –ide
Use prefixes to indicate the number of each atom
Examples:
N2O – dinitrogen monoxide
CCl4 – carbon tetrachloride

6. Prefixes
Mono –
Di-
Tri-
Tetra-
Penta-
Hexa-
Hepta-
Octa-
Nona-
Deca-

7. Diatomics There are seven elements that always exist as diatomics
Always exist bonded to themselves in nature
Example: H2
H BrONClIF or BrINClHOF

8. Practice – Name or give the Formula
NF3
P2O5 F2
OBr2
BF3
CH4 NO BN
Carbon disulfide
Selenium
Nitrogen trihydride
Sulfur dioxide
Phosphorous pentabromide
Xenon hexafluoride
Tetraarsenic decoxide
Trinitrogen nonoxide

9. Answers Nitrogen trifluoride Diphosphorus pentoxide Fluorine
Oxygen dibromide
Boron trifluoride
Carbon tetrahydride
Nitrogen monoxide
Boron mononitride
CS2 Se
NH3 (ammonia)
SO2
PBr5
XeF6
As4O10
N3O9

10. Naming Binary Acids Contains Hydrogen and one other element
The first word has the prefix hydro- , the rest of the first word consists of the root of the second element plus the suffix –ic
The second word is always acid
Example
HCl : hydrochloric acid
H2S : hydrosulfuric acid

11. Practice HBr HI H3P Hydrofluoric acid Hydroselenic acid
Hydrochloric acid
Hydrobromic acid
Hydroiodic acid
Hydrophosphoric acid HF
H2Se
HCl

12. Naming Oxyacid's Contains both a hydrogen and an oxyanion (polyatomic)
Keep the root of the oxyanion
Include prefixes per- and hypo- as part of the name
If the oxyanion ends in –ate replace with –ic
If the oxyanion ends in –ite replace with –ous
The second word is acid
Example
HNO3 : nitric acid
HClO : hypochlorous acid

13. Practice H2SO4 HClO4 H3PO4 Carbonic acid Acetic acid nitrous acid
Sulfuric acid
Perchloric acid
Phosphoric acid
H2CO3
HC2H3O2
HNO2

14. What is the formula for hydroxic acid?
H2O
HOH

15. Formation of Covalent Bonds

16. Look at Fluorine
Fluorine has 7 valence electrons, it needs 1 more electron to form an octet
As two fluorine atoms approach one another attractive forces and repulsive forces act upon the two atoms
Once that atoms are close enough together they bond covalently to form a fluorine molecule.

18. Structures
Electron Dot Structure
Lewis Structure

19. Practice – Lewis Structures
PH3
H2S
CCl4

20. Answers or

21. Single Covalent Bonds They are also called sigma bonds (σ)
Sigma bonds occur when the shared pair of electrons is centered between the two atoms

22. Multiple Covalent Bonds
Atoms can share more than one pair of electrons with another atom
Double or Triple bonds
Oxygen and Nitrogen
Multiple covalent bonds consist of one sigma and at least one pi bond (π)
Pi bonds form when parallel orbitals overlap and share electrons

23. How many Sigma and Pi bonds are there?
C2H2
C2H4

24. More Lewis Structures
NF3
CO2
SiF4
CH4
OCl2
NCl3