Expert: Amy - 12/14/2004

Question
Which group 18 element is most likely to form a compound with the element flourine?
1. He
2. Ne
3. Ar
4. Kr
The answer is Kr, but I don't get why.Please explain. My teacher told us the answer, but didn't explain it well and there is a test tomorrow.Please help.


Answer
Hi,
sorry to not catch your question in time. I've had to leave my office a lot in the last week. I hope your test went well.

Here is the answer to your question

Amy

The six noble gases are found in group 18 of the periodic table. They are Helium, Neon, Argon, Krypton, Xenon, and Radon in order of increasing atomic weight. These elements were considered to be inert gases, as they have a closed-shell configuration, until the 1960's, because their oxidation number of 0 prevents the noble gases from forming compounds readily. This was found to be incorrect in 1962 when Neil Bartlett succeeded in making the first complex xenon compound. His work was confirmed by scientists at Argonne National Laboratory in Illinois, who made the first simple compound of Xenon and Fluorine (xenon tetrafluoride) and latter made Radon and Krypton compounds. Although krypton compounds were made with considerable difficulty, both xenon and radon reacted readily with fluorine, and additional reactions to produce other compounds of xenon and radon could be accomplished. All noble gases have the maximum number of electrons possible in their outer shell (2 for Helium, 8 for all others), making them stable.


Krypton, Xenon, and Radon, being the heaviest inert gases, have been known to form chemical combinations as stated before above. This is due to the forces between the outermost electrons of these three elements and their nuclei are diluted by the distance and the interference of other electrons. The energy gained in creating a Xenon or Radon Fluoride is greater than the energy required for promotion of the reaction, and the compounds are chemically stable. Compounds of Helium, Neon, or Argon, the electrons of which are more closely bound to their nuclei, are unlikely to be created