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14Si28.085
Metalloids (Semimetals)solid at STPP-block

Silicon

Group: 14Period: 3Standard Atomic Weight: 28.085 u

Why is Silicon in this position?

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

Group Assignment
Group 14

Belongs to Group 14 because it has 4 valence electrons (3s² 3p²).

Period Assignment
Period 3

Belongs to Period 3 because its outermost occupied shell is n=3.

Orbital Block
P-block

Belongs to the p-block because its valence electrons fill 3p subshells.

Chemical Category
Metalloids (Semimetals)

Classified as a metalloid due to its lustrous metallic appearance combined with brittle mechanical nature and semiconductor bandgap (1.1 eV).

Atomic Structure & Bohr Shell Model

Shell Distribution: [2, 8, 4]

Bohr Atomic Shell Model(2, 8, 4)

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

14 Protons (p⁺)14 Neutrons (n⁰)
KShell K: Electron 1 of 2Shell K: Electron 2 of 2LShell L: Electron 1 of 8Shell L: Electron 2 of 8Shell L: Electron 3 of 8Shell L: Electron 4 of 8Shell L: Electron 5 of 8Shell L: Electron 6 of 8Shell L: Electron 7 of 8Shell L: Electron 8 of 8MShell M: Electron 1 of 4Shell M: Electron 2 of 4Shell M: Electron 3 of 4Shell M: Electron 4 of 4SiZ = 14

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):8 / 8 electrons (100%)
Shell M (n=3):4 / 18 electrons (22%)
Aufbau Electron Configuration
1s² 2s² 2p⁶ 3s² 3p²

Neutral ground state configuration. Valence electrons: 4.

Atomic & Quantum Properties

Electronegativity (Pauling)1.9 Pauling
1st Ionization Energy786.5 kJ/mol
Electron Affinity-134 kJ/mol
Atomic Radius (empirical)111 pm
Common Oxidation States+4, -4
Crystal StructureDiamond Cubic

Physical & Thermal Properties

Density at STP2.33 g/cm³
Melting Point1414 °C (1687 K)
Boiling Point3265 °C (3538 K)
Magnetic OrderingDiamagnetic
Discovery Year1824
Discovered ByJöns Jacob Berzelius

Real-World Uses, Occurrence & Compounds

Major Industrial & Everyday Uses
  • Semiconductor microchips, computer processors, and transistors
  • Photovoltaic solar cells converting sunlight to electricity
  • Silicone polymers for sealants, medical implants, and kitchenware
  • Concrete, glass, brick, and ceramic building materials
Occurrence in Nature

Extensively present throughout Earth's mantle and crust as silica (SiO₂ / quartz) and silicate minerals (feldspar, granite).

Etymology & Name Origin

From Latin 'silex' or 'silicis' meaning flint stone

Important Chemical Compounds
SiO₂ (Silica / Quartz)
SiC (Silicon carbide / Carborundum)
SiCl₄ (Silicon tetrachloride)
CaSiO₃ (Wollastonite)
Interesting Chemical Facts
  • The global tech hub 'Silicon Valley' in California was named after the silicon wafers used in computer semiconductors.
  • Pure silicon expands when it freezes into a solid, much like water does.
  • Silicon carbide (SiC) is one of the hardest artificial ceramics, used in bulletproof vests and high-power EV inverters.
Safety & Handling Note

Elemental silicon is non-toxic, but chronic inhalation of crystalline silica dust causes silicosis, a progressive irreversible lung disease.