# Atomic structure and determing effective nuclear charge

1. Oct 29, 2008

### joker314

1. The problem statement, all variables and given/known data

The 3s state of Na has an energy of -5.14 eV. Determine the effective nuclear charge.

2. Relevant equations

Zeffective = Z - S (not listed in text book, found this online when trying to figure out the problem)

3. The attempt at a solution

Nothing in the text book in this section talk about determining nuclear charge. I know that Na is in the 2s$$^{2}$$2p$$^{6}$$ group.

2. Oct 29, 2008

### olgranpappy

For a hydrogenic atom, what is the expression for the energy-levels in terms of the principle quantum-number?

3. Oct 29, 2008

### joker314

I believe that would be 1s

4. Oct 30, 2008

### olgranpappy

no. you need an equation that relates energy "E" to the principle quantum number "n". Do you know an equation like that?

5. Nov 8, 2008

### joker314

I do now... Even though I read that response too late. The grader of my homework gave me full credit anyways for a sub-par result.... But I appreciate the response because it let me on the right track after the fact!