1. Molecular Compounds

2. Molecular Compound atoms of non-metals combine and form a pure substance example: nitrous oxide (N 2 O) 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 attraction of atoms holds them together

4. SMART Board Activity

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: ElementFormula bromineBr 2 chlorineCl 2 fluorineF2F2 hydrogenH2H2 iodineI2I2 nitrogenN2N2 oxygenO2O2

7. Other Diatomic Molecules there can be other types of diatomic molecules some can share 2 pairs of electrons e.g. O 2 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 = H 2 O hydrogen peroxide = H 2 O 2

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. P 2 O 5 is diphosphorus pentoxide di- means 2, pent- means 5

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

11. Naming Rules 1.Name the first element (e.g. nitrogen) 2.Name the second element, using the suffix “-ide” (e.g. oxide) 3.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. N 2 O

12. Hydrogen hydrogen is unique often does not follow same naming has given names: NameFormula waterH2OH2O hydrogen peroxideH2O2H2O2 ammoniaNH 3 methaneCH 4 hydrogen sulfideH2SH2S