A group 14 element is to be converted into n-type semiconductor by doping it with a suitable impurity. To which group should this impurity belong

 Silicon and germanium both have valance electrons and they belong to group 14th of the periodic table. Arsenic and phosphorus belong to group 15th of the periodic table and they have valence electrons equal to 5. When silicon or germanium is adopted with phosphorus or arsenic, four electrons of phosphorus or arsenic out of five; make covalent bonds with four electrons of silicon or germanium leaving one electron free; which increases the electrical conductivity of silicon or germanium. Since the electrical conductivity of silicon and phosphorus is increased because of negatively charged particles (electron), thus this is known as n – type semiconductor.