1. The Representative Elements: Group 5A Through 8A

2. Properties of Nitrogen
Atomic Number
Density (g/L)
Melting Point (oC)
Boiling Point (oC)
Atomic Radius (pm)
Ionic Radius, N-3 (pm) 171
Electronegativity
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3. How Air Bags Work
In an accident, sensors initiate the reaction with a spark
2NaN3(s) => 2Na(s) + 3N2(g)
reactive sodium destroyed by
10Na(s) + 2KNO3(s) => K2O(s) + 5Na2O(s) + N2(s)
heat converts hazardous products into glass
K2O(s) + Na2O(s) + SiO2(s) => glass
heat
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4. Ostwald Process: Nitric Acid
4 NH3(g) O2(g) => 4 NO(g) H2O(g)
2 NO(g) + O2(g) => 2 NO2(g)
3 NO2(g) + H2O(l) => 2 HNO3(aq) + NO(g)
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5. Nitrogen Cycle
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6. Properties of Phosphorus
Atomic Number
Density (g/L)
Melting Point (oC)
Boiling Point (oC)
Atomic Radius (pm)
Ionic Radius, P-1 (pm)
Electronegativity
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7. Phosphate Fertilizers
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9. 2Ca3(PO4)2 +6SiO2 +10C (1500°C) 6CaSiO3 + 10CO + P4
Isolation of P
2Ca3(PO4)2 +6SiO2 +10C (1500°C)      6CaSiO3
+ 10CO + P4
The reaction may proceed via "phosphorus pentoxide", P4O10
2Ca3(PO4)2 + 6SiO2      6CaSiO3 + P4O10
P4O C      10CO + P4
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10. 磷
used in the manufacture of safety matches, pyrotechnics, incendiary shells, smoke bombs, tracer bullets, etc.
Fertilisers(肥料)
phosphates are used in the production of special glasses, such as those used for sodium lamps
bone-ash, calcium phosphate, is used to produce fine chinaware and to produce monocalcium phosphate used in baking powder
important in the production of steels, phosphor bronze, and many other products
Na3PO4 is important as a cleaning agent, as a water softener, and for preventing boiler scale and corrosion of pipes and boiler tubes
pesticides (殺蟲劑)
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11. 磷循環
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12. FeAsS (700°C) FeS + As(g) As(s) 砷 bronzing pyrotechnics
doping agent in solid-state devices such as transistors
the arsenide is used as a laser material to convert electricity directly into coherent light
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13. Sulfur Isotopes
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14. Frasch Process for Extracting Sulfur
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15. concentrated (large amount of solute) strong acid dehydrating agent
Sulfuric Acid
concentrated (large amount of solute)
strong acid
dehydrating agent
oxidizing agent
industrial production
by-product of roasting of sulfide ores or from scrubbers in fossil fuel burning plants
produced from elemental sulfur by burning in air using catalysis (contact process)
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16. Properties of Sulfuric Acid
concentrated (large amount of solute)
strong acid
dehydrating agent
oxidizing agent
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17. Sulfuric Acid Production
S8(s) + 8O2(g) => 8SO2(g)
2 SO2(g) + O2(g) => 2 SO3(g)
SO3(g) + H2O(l) => H2SO4(aq)
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18. Preparation of Se
Cu2Se + Na2CO3 + 2O2      2CuO + Na2SeO3 + CO2
The selenite Na2SeO3 is acidified with sulphuric acid. Any tellurites precipitateout leaving selenous acid, H2SeO3, in solution. Selenium is liberated from selenous acid by SO2
H2SeO3 + 2SO2 + H2O      Se + 2H2SO4
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19. Downs Cell
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20. Chlor-Alkali Process
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21. Production of Phosphorus in Electric Furnace
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22. Phosphorus Allotropes
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23. Industrial Preparation by Electrolysis
Na+ + Cl- + H2O  Na+ + 1/2Cl2 + 1/2H2 + OH-
Laboratory Preparation
MnO2 + 4HCl      MnCl2 + Cl2 + 2H2O
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25. Properties of Bromine Atomic Number 35 Density (g/L) 3.12
Melting Point (oC)
Boiling Point (oC)
Atomic Radius (pm)
Ionic Radius, Br-1 (pm) 196
Electronegativity
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26. Bromine and Iodine E° = +0.293 V E° = +0.823 V Laboratory Preparation:
NaBr (s) + H2SO4 (l)  HBr (g) + NaHSO4 (s)
2HBr (g) + H2SO4 (l)  Br2 (g) + SO2 (g) + 2H2O (l)
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27. Bromine fumigants flameproofing agents water purification compounds
Use
fumigants
flameproofing agents
water purification compounds
dyes
medicines
(AgBr) used for photography
pesticides
water purification
used to make plastics
flame retardant
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28. Properties of Iodine
Atomic Number
Density (g/L)
Melting Point (oC)
Boiling Point (oC)
Atomic Radius (pm)
Ionic Radius, I-1 (pm)
Electronegativity
iodide, and thyroxin which contains iodine, are used internally in medicine. A solution of KI and iodine in alcohol is used as a disinfectant for external wounds.
silver iodide is used in photography
nutrient
added to table salt for nutrition {stops goitres, (Derbyshire neck)}
deep blue colour in a starch solution is a sign of the free element
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29. Hydrogen Halides HX
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31. bond enthalpy of HX (kJ mol-1) electron affinity of X (kJ mol-1)
hydration enthalpy of X- (kJ mol-1)
sum of these (kJ mol-1) HF
+562
-328
-506
-272
HCl
+431
-349
-364
-282
HBr
+366
-324
-335
-293 HI
+299
-295
-289
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