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2. Elemek felosztása. Nemesgázok, hidrogén, halogének és vegyületeik

2017.01.07

Inorganic Chemistry

Nonmetals

Elements

  • Three main groups:

Metals:

  • Group I-IV and the d-block
  • 1,2,3 electrons on the outer shell
  • Most of them is solid at room temperature (except mercury)
  • Shiny grey (gold: yellow, copper: reddish brown)
  • Conduct electricity and heat
  • Malleable and ductile

Nonmetals:

  • Group IV – VIII (plus Hydrogen)
  • 4,5,6,7,8 electrons on the outer shell (Hydrogen: 1, Helium: 2)
  • Gas (hydrogen, oxygen, nitrogen, chlorine)
  • Liquid (bromine)
  • Solid (carbon, sulphur, phosphor)
  • Different colours
  • Opaque or transparent
  • Fragile
  • Don’t conduct electricity and heat (insulators)

Metalloids

  • They have metallic and nonmetallic properties

 

 

Nonmetals

 

Noble gases

  • Group VIII: helium, neon, argon, krypton, xenon, radon

Structure:

They are made of individual atoms: closed outer shells

Physical properties:

  • Colourless, odorless gases
  • They aren’t soluble in water
  • They don’t conduct electricity

Chemical properties:

  • Noble gas notation: they have closed outer shell
  • Nonreactive substances: don’t form chemical bonds and compounds

Presence, occurence:

  • In the air (atmosphere)
  • In rocks
  • In crude oil and natural gas
  • In stars

Use:

  • He: filling airships, balloons
  • He: artificial air (divers)
  • Ne: „neon lights”
  • Ar: protective gas in welding
  • Kr: light bulbs
  • Rn: radioactive (danger of cancer, rock dating)

 

 

Hydrogen

Structure

  • Atom: 1 proton, 1 electron
  • Molecule: H – H, H2 (covalent bonding)

Physical properties

  • Odorless, colourless gas
  • Insoluble in water
  • Density is the smallest (14,5 times lighter than the air)

Chemical properties

  • Oxidation:
  • 2H2 + O2 = 2H2O, faint blue flame
  • Mixture of hydrogen and oxygen (2:1): explosive gas
  • Reaction with chlorine:
  • H2 + Cl2 = 2HCl
  • Reaction with copper oxide:
  • CuO (black) + H2 = Cu (red) + H2O
  • H2 is reducing agent

Occurrence

  • Volcanic gases
  • Upper atmosphere
  • In compounds (water, natural gas, crude oil, organic compounds)

Production

  • Electrolysis of water

Use

  • Production of ammonia, ammonium nitrate (fertilizer)
  • Welding

 

 

 

Group VII: Halogens

  • Name: „salt-makers”
  • Fluorine (F): pale yellow gas
  • Chlorine (Cl): yellow-green gas
  • Bromine (Br): orange-brown liquid
  • Iodine (I): grey crystals

Structure:

  • Outer shell: 7 electrons
  • In nature: diatomic molecules, covalent bonding: F2, Cl2, Br2, I2
  • Nonpolar molecules

 

Chlorine

Physical properties:

  • Yellow-green gas
  • Distinctive odor (makes cough)

Chemical properties:

  • Diatomic molecules
  • Reactive
  • Poisonous
  • Reaction with water:
  • Cl2 + H2O = HCl (hidrochloric acid) + HOCl (bleach)
  • Bleach: decolorises
  • Reaction with hydrogen:
  • H2 + Cl2 = 2HCl
  • Reaction with sodium:
  • 2Na + Cl2 = 2NaCl  redoxireaction

Occurence: in volcanic gases, in compounds

Importance:

  • Poisonous, disinfectant,
  • Industry: hydrochloric acid, pesticides, pharmaceutical industry

 

Iodine

Grey, solid crystals, vapour is violet

Solubility:

  • Slightly soluble in water
  • Soluble in alcohol (brown solution) oil, gasoline (pink solution)

Sublimation: solid transforms to gas without liquid state

Importance: disinfectant

 

Hydrogen chloride

Structure:

  • H-Cl
  • Electronegativity: H: 2.1, Cl: 3.0
  • Cl attracts the bonding electrons much more: polar bond, dipole molecule

Physical properties:

  • Colourless gas
  • Distinctive odor (makes cough)
  • Soluble in water: forms hydrochloric acid
  • :
  • HCl + H2O = H3O+ + Cl-      (acidic pH)
  • Hydronium ion and chloride ion is formed

Chemical reactions

  • Reacts with metals (except copper), hydrogen and salts are formed:
  • 2HCl + Zn = ZnCl2 + H2
  • 6HCl + 2Al = 3AlCl3 + 2H2

Occurence

  • Volcanic gases
  • Stomach

Production:

  • H2 + Cl2 = 2HCl

Use:

  • Cleaning
  • Textile, paint and pharmaceutical industry