This is a reading activity that is designed to supplement your current textbook in order to bridge the gap between the old standards and NGSS.
According to the performance expection MS-PS-1-1, students are expected to develop models to describe the atomic composition of simple molecules and extended structures. However this does not include valence electrons and bonding energy, discussing the ionic nature of subunits of complex structures, or a complete description of all individual atoms. This makes most textbooks obsolete.
I have rewritten this material to place an emphasis on compound structure rather than atoms and their valence electrons. I have included a brief overview of atomic structure in hopes that it will help you to bridge the gap between your current material and your NGSS curriculum adoption. However, this will eliminate the task of teaching students about the structure of individual atoms.
This includes an activity in which students are to create a Venn Diagram comparing and contrasting ionic and covalent compounds.