Understanding Li's Outermost Electron Ionization Energy

[Physicsiscool]

Can someone please help me understand the following question?

The ionization energy of the outermost electron in Li is 5.390 eV. What is the effective charge seen by the outermost electron? (Li has 2 energy levels)

 

[dextercioby]

Can someone please help me understand the following question?

The ionization energy of the outermost electron in Li is 5.390 eV. What is the effective charge seen by the outermost electron? (Li has 2 energy levels)

Think as Litium atom as a hydronenoid ion with one lousy electron orbiting the positively charged core (i don't call it nucleus,since it includes the other 2 electrons of Litium) of charge +Z_eff times e.
Plug it in Balmer formula (the one which assumes infinite mass nucleus and that,for the reason of simplicity) for n_1=2 and n_2=infinity and you'll get your result by a simple division.I would advise using Heaviside-Lorentz units.

 

[wais]

The effective charge seen by the outermost electron in Li can be calculated using the formula Zeff = Z - S, where Z is the atomic number and S is the screening constant. In the case of Li, the atomic number is 3 (since it has 3 protons in its nucleus) and the screening constant can be calculated by taking into account the number of electrons in the inner energy level. Since Li has 2 energy levels, it means that there are 2 electrons in the inner energy level. Therefore, the screening constant would be 2 for Li.

Plugging in these values into the formula, we get Zeff = 3 - 2 = 1. This means that the effective charge seen by the outermost electron in Li is 1. This also explains why the ionization energy of the outermost electron in Li is relatively low (5.390 eV) compared to other elements, since it only needs to overcome the attractive force of one proton in the nucleus.

Overall, understanding the effective charge seen by the outermost electron in Li helps to explain its ionization energy and provides insight into the electronic structure of the element.