Silicon atomic structure: how many valence electrons are present in a neutral silicon atom?

Introduction / Context:
Semiconductor behavior originates from atomic structure. Silicon, the workhorse of modern electronics, belongs to group 14 (IV) of the periodic table and exhibits a specific number of valence electrons that enable covalent bonding in a crystal lattice and controlled doping.

Given Data / Assumptions:

• Pure (intrinsic) silicon atom under neutral conditions.
• Basic periodic table knowledge applies.
• Valence electrons are those in the outermost shell involved in bonding.

Concept / Approach:
Group 14 elements (C, Si, Ge, Sn, Pb) each have four valence electrons. In crystalline silicon, each atom forms four covalent bonds with neighbors by sharing these electrons. Doping with group 15 (five valence electrons) or group 13 (three valence electrons) introduces extra electrons or holes, respectively, modifying conductivity.

Step-by-Step Solution:
Identify silicon’s group: group 14 → four valence electrons.Relate to bonding: four covalent bonds per atom in the lattice.Conclude the number: 4 valence electrons.

Verification / Alternative check:
Electron configuration of Si: [Ne] 3s2 3p2 → total of four electrons in the outer shell (3s and 3p), confirming the count.

Why Other Options Are Wrong:
0, 1, or 2: do not match group 14 and fail to explain silicon’s tetravalent bonding.None of the above: incorrect because 4 is correct.

Common Pitfalls:
Confusing valence electron count with charge carriers in doped silicon; mixing up group numbering schemes (old IV vs modern 14).

Final Answer:
4