Question 21 • GA-GSE Physical Science A
Silicon has four valence electrons, while arsenic has five, and arsenic has one more electron shell because it is in a lower period on the periodic table. In the silicon crystal, arsenic uses four electrons to form bonds and can donate its extra electron to conduct electricity. This adds mobile electrons and increases conductivity, matching “one more valence electron and more electron shells” and “conductivity increases because the arsenic atom loses the electron.”
AI-written and checked against the verified answer.