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7N14.007
Reactive Nonmetalsgas at STPP-block

Nitrogen

Group: 15Period: 2Standard Atomic Weight: 14.007 u

Why is Nitrogen in this position?

Understanding the scientific rationale behind Nitrogen's position in the periodic table:

Group Assignment
Group 15

Belongs to Group 15 (Pnictogens) because it possesses 5 valence electrons (2s² 2p³).

Period Assignment
Period 2

Belongs to Period 2 because its valence electrons occupy principal shell n=2.

Orbital Block
P-block

Belongs to the p-block because the differentiating electron enters a 2p subshell.

Chemical Category
Reactive Nonmetals

Classified as a reactive nonmetal due to its high electronegativity (3.04) and capability to form gaseous covalent molecules.

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 5]

Bohr Atomic Shell Model(2, 5)

Hover or tap any shell orbit ring to inspect electron counts and 2n² capacities.

7 Protons (p⁺)7 Neutrons (n⁰)
KShell K: Electron 1 of 2Shell K: Electron 2 of 2LShell L: Electron 1 of 5Shell L: Electron 2 of 5Shell L: Electron 3 of 5Shell L: Electron 4 of 5Shell L: Electron 5 of 5NZ = 7

Educational Note: This Niels Bohr planetary model visually illustrates principal quantum energy shells ($n=1, 2, 3\dots$) and electron counts. In modern quantum mechanics (Schrödinger model), electrons do not orbit in fixed circular planetary tracks, but exist as 3D probability clouds (orbitals: $s, p, d, f$) governed by the Heisenberg uncertainty principle.

Electron Shell Filling Breakdown

Shell K (n=1):2 / 2 electrons (100%)
Shell L (n=2):5 / 8 electrons (63%)
Aufbau Electron Configuration
1s² 2s² 2p³

Neutral ground state configuration. Valence electrons: 5.

Atomic & Quantum Properties

Electronegativity (Pauling)3.04 Pauling
1st Ionization Energy1402.3 kJ/mol
Electron Affinity7 kJ/mol
Atomic Radius (empirical)56 pm
Common Oxidation States+5, +3, -3
Crystal StructureHexagonal

Physical & Thermal Properties

Density at STP0.00125 g/cm³
Melting Point-210 °C (63.15 K)
Boiling Point-195.79 °C (77.36 K)
Magnetic OrderingDiamagnetic
Discovery Year1772
Discovered ByDaniel Rutherford

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Industrial fertilizer production via Haber-Bosch ammonia synthesis
  • Cryogenic liquid nitrogen for biological sample preservation and surgery
  • Protective inert gas blanketing for food preservation and electronics assembly
  • Chemical propellants, gunpowder, and commercial explosives
Occurrence in Nature

Constitutes 78% of Earth's atmosphere by volume; essential structural element of amino acids, proteins, and genetic DNA/RNA.

Etymology & Name Origin

From Greek 'nitron' and 'genes' meaning nitre-forming

Important Chemical Compounds
NH₃ (Ammonia)
HNO₃ (Nitric acid)
N₂O (Nitrous oxide)
NO₂ (Nitrogen dioxide)
NaNO₃ (Sodium nitrate)
Interesting Chemical Facts
  • The N≡N triple bond requires a colossal 945 kJ/mol of energy to break, explaining why molecular nitrogen is so chemically inert.
  • Saturn's largest moon, Titan, boasts a thick atmosphere comprised of 98% nitrogen.
  • Lightning strikes provide sufficient natural energy to split atmospheric N₂ molecules, creating natural nitrate fertilizers.
Safety & Handling Note

Liquid nitrogen causes rapid severe cryogenic frostbite; unventilated N₂ gas can lead to instant silent asphyxiation.