Consider the isoelectronic ions F- and Na+. (d) For isoelectronic...

Question

Consider the isoelectronic ions F- and Na+. (d) For isoelectronic ions, 
how are effective nuclear charge and ionic radius related?

Accepted Answer

hey everyone in this example, we need to determine the relationship between ionic radius and effective nuclear charge. For the isil, electronic ions, chloride and potassium atom. We should recall that ice electronics corresponds to atoms or ions with the same electron configuration and the same number valence electrons. So looking at our chloride and potassium cat ion, we would recognize that they have the same noble gas configuration which is for the noble gas argon. Next we want to recall the fact that for neutral atoms atomic and ionic radius is the same. However, if we lose a valence electron where we would form therefore a cat ion, we would therefore say that the ionic radius of the atom is going to be decreased or smaller. So it decreases. We can say so to explain the relationship between ionic radius and effective nuclear charge. We want to say that for so electronic ions, the electron configuration and shielding values are the same. We should recall that shielding values are represented by the capital S here. And this refers to our core electrons repelling our outer valence electrons. And we would also recall that only nuclear charge changes. And so we would recall that nuclear charges represented by the symbol Z. And so we can say that therefore as our nuclear charge increases, our effective nuclear charge also will increase and therefore our ionic radius is going to decrease. So it would make sense that because the chloride and potassium carry on have the configuration for Argon, which has the atomic number 18. So let's make this clear argon has the atomic number 18. This increase in atomic number, increases our effective nuclear charge of our ions as well as decreases our ionic radius of these ions. And it also makes sense for potassium because even though potassium has a higher atomic number being 19 on our periodic table, we would recognize that because it has this positive charge here, meaning we would lose a valence electron. It therefore has a decreased ionic radius. And so this this explanation down here would be our final answer for the relationship between ionic radius and effective nuclear charge. I hope that everything I explained was clear. If you have any questions, please leave them down below and I will see everyone in the next practice video.

Consider the isoelectronic ions F- and Na+. (d) For isoelectronic ions, how are effective nuclear charge and ionic radius related?

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