question 2.93

[Blake_Katsev_2E]

hi Im having a hard time understanding question 93. I feel like by sodium giving off an electron and thus a shell it should get smaller but it doesn't. Also now that Cl gained another electron I feel like it should be bigger because of electron electron repulsions but it is not.

[Monica Habashy 3A]

Yeah! Why would that not be the case?

[Blake_Katsev_2E]

no that isnt the case. It says that Cl get smaller and Na gets bigger in the solutions manual...

[Alexandra_Ivanova_1A]

I believe there is an error in the solutions manual. On Lavelle's website, the "Solutions Manual Errors" state:

2.93 In the picture, it shows A (smaller atom) + B (larger atom) --> C (larger ion) + D (smaller ion)
The solution manual says that A=Na and B=Cl, and it references Figure 2.20 which explicitly lists the atomic radius of Na to be 154 pm and the atomic radius of Cl to be 99 pm. It also says that C= Na+ and D= Cl-, referencing Figure 2.22 which shows that the ionic radius of Na+ to be 102 pm and the ionic radius of Cl- to be 181 pm.
Error: A=Na; B=Cl; C=Na+; D=Cl-. Correction: A=Cl ; B=Na; C=Cl-; D= Na+

Hopefully that clears it up!