why the valence of silicon is 4

The valence of an element refers to the number of electrons in the outermost energy level (valence shell) of its atomic structure. For silicon (Si), which is in Group 14 of the periodic table, its atomic number is 14. This means that silicon has 14 electrons. The electron configuration of silicon is 1s² 2s² 2p⁶ 3s² 3p².

The valence electrons are the electrons in the outermost energy level, which is the 3rd energy level (designated as the 3s² 3p² in silicon's electron configuration). So, silicon has 4 valence electrons.

The number of valence electrons in an element is important because it determines its chemical properties and how it bonds with other elements to form compounds. Silicon, with its 4 valence electrons, can form covalent bonds with other elements and is a key component in many semiconductor materials.