Question Detail
Question
Example: The electron configurations change from Li ([He]2s¹) to Be ([He]2s²) to B ([He]2s²2p¹), showing addition to the __________ shell.
Correct Answer
Option B is the correct answer.
Detailed Explanation
Across period 2, electrons are added to the valence shell (n=2), progressing from the 2s to the 2p orbitals.
Hint
The outermost shell being filled.