Common electronic configuration
ns2 np4
Valences
2 & 4 (but O differs)
What are the metallic characters of 16th group elements
O and S are non-metals
Se, Te, Po show both metal and non-metal characters
What is the only element in 16th group which exists in gaseous state?
O
Oxidation states
Except O, other elements in the group can form even numbered oxidation states from -2 upto +6
What are the 16th group hydrides?
H2O
H2S
H2Se
H2Te
2 allotropic forms of oxygen
O2 and O3
Describe O3
Ozone is a light blue colored (colorless) gas with a pungent odor
What special properties does O3 have due to its ability to produce atomic oxygen?
Describe O2
O2 is colorless, and odorless
Slightly water soluble
How is O2 prepared in the laboratory?
Catalytic decomposition of KClO3
KClO3 ———-> KCl + O2
(heating with MnO2 or Pt)
Catalytic decomposition of H2O2
H2O2 ——-> H2O + O2
(heating with MnO2)
How is O2 produced industrially?
By fractional distillation of liquid air
What is the most widely used solvent?
water
Show the ionization of H2O
2H2O —> OH- + H30+
revers.
Show water’s reactions with acids and bases
NH3 + H2O —> NH4+ + OH-
HCl + H20 —–> Cl- + H3O+
water’s reaction w bases
NH3 + H2O —> NH4+ + OH-
water’s reaction w acids
HCl + H20 —–> Cl- + H3O+
Why is water considered amphiprotic?
It can either donate or accept a proton
Decomposition of H2O2 in sunlight
H2O2 —>H2O + O2
So, H2O2 is usually stored in brown or black colored bottles
Describe H2O2
How does H2O2 release atomic oxygen
H2O2 —-> H2O + O
uses of H2O2
Oxidizing agent
Disinfecting agent
Bleaching agent
Reducing agent
Used as a rocket fuel
Properties of H2O2
How does H2O2 react as an oxidizing agent?
H2O2 —> H2O
I- —> I2
H2O2 —> H2O
Fe2+ —> Fe3+