Answer: The correct options are A and D.
Explanation: We are provided with some elements and we need to find which element will loose three electrons to empty its valence shell.
Valence electrons are the electrons present in the last shell that can be easily knocked off.
Valence electrons in Aluminium (Al) = 3
Valence electrons in Sulfur (S) = 6
Valence electrons in Nitrogen (N) = 5
Valence electrons in Scandium (Sc) = 3
From the valence electrons, it can be seen that Scandium and Aluminium are the elements that can loose three electrons.
Therefore, Option A and D are correct.
