1. Molecular Compounds

2. Molecular Compound
atoms of non-metals combine and form a pure substance
example: nitrous oxide (N2O)
the atoms are joined by covalent bonds
each bond shares a pair of electrons
bonded atoms form a MOLECULE

3. Covalent Bonds connection where two atoms share a pair of electrons
the electron pair belongs to both atoms

4. CovalentBonding.notebook

5. Remembering Non-Metals
non-metal valence shells are almost full
the spaces can attract other electrons
allows non-metals to get close to each other
the two nuclei form strong attractions for each other’s electrons
but not strong enough
net effect – share the electrons

6. Molecular Elements
molecular elements are two or more atoms of the same element
a molecule made of only two atoms is called a diatomic molecule
Molecular Elements that Commonly Form Diatomic Molecules:
Element
Formula
bromine
Br2
chlorine
Cl2
fluorine F2
hydrogen H2
iodine I2
nitrogen N2
oxygen O2

7. Other Diatomic Molecules
there can be other types of diatomic molecules
some can share 2 pairs of electrons
e.g. O2
other diatomic molecules can be made of two different elements
e.g. hydrogen and fluoride HF

8. Properties of Molecular Compounds
at room temperature they can be liquid, solid or gas
generally soft solids
if dissolved in water, they do not conduct electricity
have relatively low melting points
two non-metallic elements can combine in different ways and form different compounds
e.g. hydrogen and oxygen:
water = H2O hydrogen peroxide = H2O2

9. Naming Molecular Compounds
any molecular compound that contains two elements and does not contain hydrogen uses Greek prefixes
the prefix indicates how many atoms of each element are in the compound
e.g. P2O5 is diphosphorus pentoxide
di- means 2, pent- means 5

10. Number of Atoms
Prefix 1
mono- 2
di- 3
tri- 4
tetra- 5
penta- 6
hexa- 7
hepta- 8
octa- 9
nona- 10
deca-

11. Naming Rules e.g. N2O Name the first element (e.g. nitrogen)
Name the second element, using the suffix “-ide” (e.g. oxide)
add prefixes to indicate the number of each atom (e.g. dinitrogen monoxide)
Note: mono is not used in first element; if it is required before oxide, the last “o” in prefix is dropped
e.g. N2O

12. Hydrogen hydrogen is unique often does not follow same naming
has given names:
Name
Formula
water
H2O
hydrogen peroxide
H2O2
ammonia
NH3
methane
NH4
hydrogen sulfide
H2S

13. REVIEW: Ionic and Covalent Bonds
Ionic and Molecular Compounds.avi

14. SMARTBoard Naming
Gizmo Link

15. Activity: Look at your cue card You need to find your match!
Everyone’s card is either:
first element in a molecular compound
second element in a molecular compound
the complete compound
in either text or symbols