Question: how many electrons are in the valence shell of lithium?
Answer: Helium has 2 electrons --- both in the first shell (so two valence electrons). Lithium has 3 electrons --- 2 in the first shell, and 1 in the second shell (so one valence electron). Beryllim has 4 electrons --- 2 in the first shell, and 2 in the second shell (so two valence electrons).