# Effective Nuclear Charge for Sodium Atom

1. Apr 3, 2016

1. The problem statement, all variables and given/known data
The 3s state Na has an energy of -5.14 eV. Determine the effective nuclear charge.

2. Relevant equations
$Z_{eff} = Z - s$ Where Z is the atomic number and s is the number of shells in inner orbits.

3. The attempt at a solution
The textbook doesn't go into much more detail than this. All I have is $Z_{eff} = 11 - 10 = 1e$ The correct answer is 1.14e. How do I incorporate energy into my calculations. I understand that that a higher negative energy would imply a higher effective charge because of the greater attraction, but analytically, I do not know how to get there.

2. Apr 4, 2016

### drvrm

there are some ways to calculate it-
http://www.wikihow.com/Determine-Screening-Constant-and-Effective-Nuclear-Charge

write down the equation for energy state and use it to calculate zeffective