Silicon valence electrons — periodic table recall How many valence electrons does a silicon (Si) atom possess?

Difficulty: Easy

Correct Answer: 4

Explanation:


Introduction / Context:
Semiconductor bonding and band structure originate from the valence electron configuration. Silicon, the workhorse of microelectronics, forms covalent bonds using its outer-shell electrons.



Given Data / Assumptions:

  • Element: Silicon (Z = 14).
  • Electronic configuration (ground state): 1s² 2s² 2p⁶ 3s² 3p².


Concept / Approach:
Valence electrons are those in the outermost shell participating in bonding. For Si, the outer shell is n = 3 with 3s² 3p², totaling 4 valence electrons. This tetra-valence enables sp³ covalent bonding in the diamond cubic crystal structure.



Step-by-Step Solution:
Identify outer shell: n = 3.Count electrons in 3s and 3p: 2 + 2 = 4.Hence, valence electrons = 4.



Verification / Alternative check:
Group IV (14) elements in the periodic table (C, Si, Ge, Sn) all have 4 valence electrons, consistent with tetrahedral bonding.



Why Other Options Are Wrong:
2, 1, or 0 contradict the electron configuration; 6 would suit Group 16 elements, not Group 14.



Common Pitfalls:
Confusing total electrons with valence electrons; overlooking shell structure.



Final Answer:
4

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