Calculating Zeff in Xenon (Z=54) for M (n=3) Shell

[xinlan]

Homework Statement

In xenon (Z = 54), what is the effective charge Zeff experienced by an electron in the M (n=3) shell?

Homework Equations

Zeff = Z - total electrons in K and L shells

The Attempt at a Solution

I think total electrons in K shell are 8 and in L shell are 18
then Zeff = 54-26 = 28

but I got wrong..

please help me..

 

[xinlan]

never mind.. I got it.. :)

 

[vachan]

how>?