Question

Which one of the following does not exist?
(A) $ XeO{F_4} $
(B) $ Ne{F_2} $
(C) $ Xe{F_2} $
(D) $ XeF $

Answer 1

Hint :Noble gases are generally colourless, odourless, tasteless, and also non-flammable. They were once called the group $ 0 $ in the periodic table because they believed that these gases had a valence of zero that means their atoms cannot combine with atoms of other elements to form compounds.

Complete Step By Step Answer:
These gases generally have similar properties under standard conditions. They are monatomic gases with very low chemical reactivity. The noble gases are chemical elements in group $ 18 $ of the periodic table. They are highly stable as they have the maximum number of valence electrons that their outer shell can hold. So, they rarely react with other elements as they are already very stable. These are not flammable. Noble gases are not very toxic but they are harmful in large amounts. These gases replace oxygen in the air so there is less oxygen to breathe. The atoms of noble gases have complete outer shells, so they have no tendency to lose, gain or share their electrons. This is the reason why noble gases are inert and do not take part in any chemical reactions. $ Ne{F_2} $ does not exist as it would require d orbitals for bonding which neon does not have as it belongs to the second period and also a lot of energy would be needed to excite the electrons to a higher energy level as the valence electrons are very close to the nucleus.
Therefore, option B is the correct answer.

Note :
Only some noble gases like krypton, xenon and radon form stable compounds. The compounds of these noble gases are powerful oxidizing agents and they have potential value as reagents in the synthesis of some other chemical compounds. In Xenon, the electron attraction to the nucleus is weaker as it is large in size. It can react with fluorine which is highly electronegative and has a very small size. So, the valence electron of xenon is attracted by fluorine which helps in compound formation.