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How does arsenic create n-type silicon?

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A periodic table element square for silicon shows atomic number 14, symbol Si, atomic weight range, electron configuration, and name. Icons indicate it is a solid nonmetal with diamond crystal structure and equal relative strength. Labels explain each property. — silicon Chemical properties of the element silicon.

To create n-type silicon, a process called doping is used to intentionally introduce impurities into the pure silicon crystal lattice.12

Silicon atoms have four outer electrons, which they share with four neighboring atoms to form covalent bonds. When an arsenic atom—which is pentavalent, meaning it has five outer electrons—is substituted for a silicon atom in the crystal, four of its electrons participate in bonding with the surrounding silicon atoms.132

The fifth electron from the arsenic atom does not participate in a covalent bond and is instead "donated" to the conduction band. Because this added electron is free to move through the crystal, it increases the material's electrical conductivity. The silicon is then classified as n-type (n for negative) because the primary charge carriers are these negatively charged electrons, and the arsenic atom acts as a donor.1243