Which sublevel contains valence electrons in an atom of magnesium (Mg)?

In an atom of magnesium (Mg), the valence electrons are found in the 3s sublevel. Magnesium has an atomic number of 12, and its electron configuration is 1s² 2s² 2p⁶ 3s². The two electrons in the 3s sublevel are the valence electrons that participate in chemical bonding.