Question

How many effective Na+ ions are present in rock salt NaCl if
ions along one axis joining opposite faces are removed?​

Answer 1

Answer:

Here the ions on the joining forces won't be included.

And the ions on the middle wall face not included.

So for Cl----->$(8*\frac{1}{8} )+(4*\frac{1}{2} )$

                     =3

For $Na^{+}$----->$\frac{1}{4} *12$

                                      =3

So the number of $Na^{+}$ ions are 3

$Cl^{-}$ ions are 3