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Nitrogen Group Elements and Transition Metals Properties

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Group 15 Elements (Nitrogen Family)

The nitrogen family (Group 15) includes Nitrogen (N), Phosphorus (P), Arsenic (As), Antimony (Sb), and Bismuth (Bi).

Physical Properties

  • Allotropy: Phosphorus, Arsenic, and Antimony exhibit allotropy.
  • Phosphorus: White phosphorus is highly active, while other forms are relatively inactive.

Oxides of Nitrogen

  • N2O: Nitrous oxide (laughing gas).
  • NO: Nitric oxide (paramagnetic).
  • NO2: Nitrogen dioxide.
  • N2O4: Dinitrogen tetroxide (diamagnetic).

Ammonia and Nitric Acid

Ammonia (NH3) reacts with water to form ammonium hydroxide (NH4OH). Nitric acid (HNO3) is produced via the Ostwald process using a platinum catalyst.

Nitric Acid Properties

  • Commercial HNO3 (~15M) often appears yellow due to dissolved nitrogen oxides.
  • It acts as a powerful oxidizing agent.
  • Reactions with metals: Dilute HNO3 reacts with active metals to produce hydrogen, while concentrated HNO3 typically produces nitrogen oxides.
  • Reactions with non-metals: Concentrated HNO3 oxidizes non-metals into their respective oxoacids.

Transition Metals

Key features include incomplete d-subshells, compact atomic packing, small atomic radii, and strong metallic bonding, resulting in high density and high melting points.

  • Properties: Most ions are colored, paramagnetic, act as Lewis acids, and function as excellent catalysts.
  • Common Elements: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu.

Chromium (Cr)

Electron configuration: [Ar] 3d54s1. Common oxidation states: +2, +3, +6.

  • Cr2+: Acts as a strong reducing agent.
  • Dichromate (Cr2O72-): A powerful oxidizing agent.
  • pH Dependence: The equilibrium between chromate (CrO42-) and dichromate (Cr2O72-) depends on the pH of the solution.
  • Applications: Used in stainless steel production and protective chrome plating.

Manganese (Mn)

Electron configuration: [Ar] 3d54s2. Known mineral: Pyrolusite (MnO2).

  • Oxidation States: Ranges from +2 to +7.
  • MnO2 (+4): Used in batteries.
  • Permanganate (MnO4-, +7): A powerful oxidizing agent in both acidic and basic media.

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