The penultimate and outermost orbit of an element contains 10 and 2 electrons, respectively. If the — Atomic Structure Chemistry Question

💡 Solution & Explanation

Outermost orbit is the 4th orbit, meaning $n=4$. It has 2 electrons ($4s^2$). The penultimate orbit is $n=3$, containing 10 electrons ($3s^2 3p^6 3d^2$). The inner orbits $n=1$ and $n=2$ are fully filled with 2 and 8 electrons, respectively. Total electrons = $2 + 8 + 10 + 2 = 22$. Therefore, correct answer is B.