why is (CN-)ion bigger than (I-) ion and why is (RO-) smaller than (I-) ion
thanks for your help
thanks for your help
quick gchem Q
- Thread starter tRNA
- Start date
from the kaplan white book, orgo section page 288, where it discussed nucleophiles, under size and polarizability subtitle, it says nucleophilic ability doesn't necessarily correlate to basicity. in protic solvents "large" atoms tend to be better nucleophiles...
then it gives a list of nucleophiles, best one is the largest one
CN->I->RO->....
so CN is the largest that's why it's the best Nu, but i was trying to confirm from the atomic radius trend why is I- is smaller than CN and I couldn't tell why? so really i am asking how do you compare size when the atoms you are comparing are in different periods and groups?
i know if your trying to determine size of ions and the atoms are in different periods and groups you look at the "electron configuration" and the "nuclear charge", for example if both have the same electron config. then the smallest ion will have the largest number of protons or atomic number, but i still couldn't figure out why CN- is larger than I and why RO- is smaller than I-
plz help
then it gives a list of nucleophiles, best one is the largest one
CN->I->RO->....
so CN is the largest that's why it's the best Nu, but i was trying to confirm from the atomic radius trend why is I- is smaller than CN and I couldn't tell why? so really i am asking how do you compare size when the atoms you are comparing are in different periods and groups?
i know if your trying to determine size of ions and the atoms are in different periods and groups you look at the "electron configuration" and the "nuclear charge", for example if both have the same electron config. then the smallest ion will have the largest number of protons or atomic number, but i still couldn't figure out why CN- is larger than I and why RO- is smaller than I-
plz help
- Joined
- Dec 2, 2006
- Messages
- 1,523
- Reaction score
- 4
Dear tRNA
thanks for your reply, I like your questions, I studid all material I had solomon, high yeild, Kaplan, shouam's outline,mccmurry, to find your answer, actualy, there is not such a thing you and I were thinking about, in kaplan starting with basic and nuclofhilic and how they are related, in solmon chem explains: sometimes basic and nuclofhili doesn't corelarte each other and bring out this example CN- and OH-. in kaplan what giving you is combination of nuclofhilic strenths ! that means after considering the all situations you have, like basic , size, or polarity and exc.. come to this arrangment in poretic solvent
HS->CN->I->RO->OH-.....
I did add HS to your arrangment to complete your list 🙂
I hope it helped
thanks for your reply, I like your questions, I studid all material I had solomon, high yeild, Kaplan, shouam's outline,mccmurry, to find your answer, actualy, there is not such a thing you and I were thinking about, in kaplan starting with basic and nuclofhilic and how they are related, in solmon chem explains: sometimes basic and nuclofhili doesn't corelarte each other and bring out this example CN- and OH-. in kaplan what giving you is combination of nuclofhilic strenths ! that means after considering the all situations you have, like basic , size, or polarity and exc.. come to this arrangment in poretic solvent
HS->CN->I->RO->OH-.....
I did add HS to your arrangment to complete your list 🙂
I hope it helped
