The structural analysis of silicon atoms can be discussed from multiple aspects such as their electronic configuration, covalent bond formation, hybridization mode, and physical and chemical properties.
1. Electronic configuration
Silicon atoms (Si) are located in the fourth period and group IVA of the periodic table, and their atomic number is 14. The electronic configuration of silicon atoms follows the construction principle, that is, the electrons are outside the nucleus, and they surround layer by layer from low to high energy levels, from inside to outside. Specifically, the electronic configuration of silicon atoms is 1s²2s²2p⁶3s²3p², that is, there are 2 electrons in the innermost layer (first layer), 8 electrons in the second outer layer (second layer), and 4 electrons in the outermost layer (third layer). These 4 outermost electrons are the valence electrons of silicon atoms, which play a key role in chemical reactions.
2. Covalent bond formation
Silicon atoms tend to achieve a stable electronic configuration (similar to inert gases) by sharing their valence electrons with other atoms. Specifically, silicon atoms can achieve a stable 8-electron (or 2-electron pair) configuration by sharing a pair of electrons with each of the surrounding atoms to form four covalent bonds. The formation of this covalent bond is the basis for the stability of silicon atoms in nature and in many compounds.
3. sp³ hybridization
In order to form covalent bonds that are equidistantly distributed in four directions, the outermost s orbital (1) and three p orbitals (3) of the silicon atom are hybridized to generate four sp³ hybrid orbitals. These hybrid orbitals have the same shape (tetrahedral distribution) and energy, each orbital accommodates one electron, and can form stable covalent bonds with the electrons of adjacent atoms. This hybridization enables silicon atoms to form a stable tetrahedral structure when forming compounds.
4. Physical properties
Silicon has many unique physical properties. First, silicon is a very hard material with a Mohs hardness of about 7, second only to diamond and boron carbide. Second, silicon is a semiconductor material with a conductivity between conductors and insulators. At room temperature, the conductivity of silicon is very low, but when heated, its conductivity increases rapidly. In addition, silicon has excellent thermal conductivity and high transmittance (in visible light and near-infrared bands), which makes silicon widely used in electronics, optical fiber communications and other fields.
V. Chemical properties
The chemical properties of silicon are relatively stable, and it is difficult to react with other substances (except hydrogen fluoride and alkali solution) at room temperature. Silicon can react with alkali metal hydroxide solution to form silicate and hydrogen, which is an important chemical property of silicon. In addition, silicon can also react with some non-metallic and metallic elements at high temperature to form silicide.