K.C.S.E Physics Q & A - MODEL 2013PP2QN13

K.C.S.E Physics Q & A - MODEL 2013PP2QN13

​When a germanium crystal is doped with arsenic, it becomes an N-type semiconductor. Explain how this change occurs. 
(Number of electrons in the outermost shell for germanium = 4. Arsenic = 5)

answer

•  Arsenic shares 4 of its 5 electrons with germanium. 
• the extra electron is free for conduction.