# Emission line of ions

1. Nov 8, 2007

### spideyinspace

Emission line is unique for all elements and i think it depends on the electrons of the elements...my doubt is if an element gains or loses one electron then would the emission line of this ionised atom and the emission line of its neighbor atom in the periodic table is same or not..since the ionised atom and its neighbor will have same number of electrons...

if its same then how shall we differentiate the two lines...if it is not same then how shall we say that emission line depends on electrons...i think i have explained what i meant..i think i lack some fundamental concept here and hence am posting this question...

2. Nov 8, 2007

### malawi_glenn

It depends on the number of protons and number of electrons. You get a different potential depending on how many protons you have and also the electrons interact with each other. And why do you ask this in sub-atomic forum?

3. Nov 8, 2007

### spideyinspace

do u mean the emission line of an atom and the emission line of the same atom having different no.of electrons are different...then how shall we identify an atom if the same atom has different emission spectrums..

this thread is moved from nuclear/particle physics...

4. Nov 8, 2007

### malawi_glenn

....

every kind of atom (element) has its fingerprint spectra, no other element has the same.

So carbon has totaly different spectra than nitrogen etc. Since carbon has 6protons and 6electrons and nitrogen 7protons and 7 electrons.

The differnces between CI and CII (I means neutral and II means first ionized) are very very very small, and you need high temp to have much CII (Saha equation).

There is a difference between the ionization spectra and the excitation spectra of an atom. ionization means that you lift the energy to n = infinity.

But as an example, NI and CII does not have the same excitation- and ionizaion spectra, even though they have the same number of electrons. That is due to they have different attractive potential (different # of protons)

5. Nov 8, 2007

### spideyinspace

Thank you for the clear explanation...

6. Nov 8, 2007

### Gokul43201

Staff Emeritus
To illustrate that the number of protons is also of great importance, consider the following case: Fe, Co & Ni are neighbors with Z=26, 27 & 28 respectively. If you use the isoelectronic argument, you would expect IE3(Ni) = IE2(Co) = IE1(Fe), but in reality, it is almost 4*IE1(Fe) = 2*IE2(Co) = IE3(Ni). Moreover, their first ionization energies differ by barely 1 or 2%.