Question

what is an electron configuration? a description of where valence electrons are in an atom a model to predict the mass of the molecule a representation of the protons in an atom a list of where all the electrons are located in an atom

Explanation:

To determine the correct answer, we analyze each option:

• Option 1: Electron configuration is not just about valence electrons (outermost), it's about all electrons. Eliminate.
• Option 2: Electron configuration doesn't predict molecular mass. Molecular mass is related to atomic masses. Eliminate.
• Option 3: Electron configuration is about electrons, not protons. Protons are in the nucleus and their arrangement is not what electron configuration describes. Eliminate.
• Option 4: Electron configuration is a list (or notation) that shows the location (in energy levels, sublevels, orbitals) of all electrons in an atom. This matches the definition.

Answer:

The correct option is the one with "a list of where all the electrons are located in an atom" (the fourth option in the list of choices).