A model that shows only the valence electrons in an atom is called a Lewis dot structure.

Here's why:

* Valence Electrons: These are the electrons in the outermost energy level of an atom, and they are the ones involved in chemical bonding.

* Lewis Dot Structure: This is a simplified representation of an atom where the symbol of the element is surrounded by dots that represent the valence electrons.

Let me know if you'd like an example of a Lewis dot structure!