LAB: Formula Writing and Naming of Precipitates (double replacement reactions)

In this virtual lab I prepared for my students (see link below), a variety of precipitate (double replacement) reactions are shown, which students use to practice writing ionic compound names and writing formulas. The mechanism of precipitate formation is explained, as well as brief explanations for: rules of nomenclature and formula writing, ion dissociation in water, aqueous reactions, precipitates, and solubility.

[sohamghaisas]

Electrons are found (most probably) inside the orbitals. But isn't the 1s subshell 'inside' the 2s subshell ? So isn't it a part of the 2s subshell ? So why aren't electrons found in 1s included in 2s ?