“Located” could be an intriguing topic given that electrons can be defined in Schrodinger’s Equation as a thing that is akin to a standing wave within an atom.
Valence electrons do not stand out in this. In the case of a one that is a valence electron happens an s-orbital, it also has a higher probability of being inside the nucleus. However, it is not confined to the nucleus. The precise distribution of the electron’s distribution will depend on the orbital type.
What this question could mean as well as the other questions they focus on is the location of this in relation to energy and distance to the nucleus. In answer to that question, electrons that are valence are located at the most energetic level of atoms in the ground state and thus have their most distant location away from the nucleus’s centre which is why valence electrons are ones who participate in the process of chemical bonding.
Image courtesy of 1.5: Atomic Orbitals
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