For a silicon atom, the number of electrons at the external energy level and the charge of the nucleus are equal, respectively.

The chemical element silicon in the periodic system of DI Mendeleev is in the third period of the fourth group of the main subgroup (the fourth “A” group). Since silicon is located in the third period, then all the electrons of an atom of a given chemical element will be distributed into three electronic layers (levels). The number of electrons is equal to the charge of the atomic nucleus, and the charge of the atomic nucleus, in turn, is equal to the atomic number of the element. The atomic number of the chemical element silicon is fourteen. This means that the charge of the nucleus of a silicon atom and the number of its electrons will also be equal to fourteen. Knowing that a maximum of two and eight electrons can be located on the first and second electron layers of an atom of a chemical element, respectively, we determine the number of electrons on the outer electron layer (14- (2 + 8)). It will be equal to four.