Here's how to figure that out:

* Electronic Configuration: Chlorine has an electronic configuration of 2, 8, 7. This means it has 2 electrons in its first shell, 8 electrons in its second shell, and 7 electrons in its third shell.

* Inner Shells: The inner shells are the shells closer to the nucleus (in this case, the first and second shells).

* Total Inner Shell Electrons: Therefore, chlorine has 2 + 8 = 10 inner shell electrons.