Question

Which one of the following does not exist?

• A. ${\mathrm{XeOF}}_4$
• B. ${\mathrm{NeF}}_2$
• C. ${\mathrm{XeF}}_2$
• D. ${\mathrm{XeF}}_6$

Answer 1

The correct option is B

${\mathrm{NeF}}_2$

The explanation for the correct option

(B) ${\mathbf{NeF}}_{\mathbf{2}}$

Chemical Properties of Noble Gases

• Noble gases have negligible chemical reactivity and are odorless, colorless, non-flammable, and monotonic.
• Noble gases are particularly stable because their valence electron shells are full.
• Since they have a low potential to gain or lose electrons, they are unlikely to establish chemical bonds.

${\mathbf{NeF}}_{\mathbf{2}}$

• ${\mathrm{NeF}}_2$ does not exist.
• Bonding would need the use of a $d$ orbital, which neon $\left(\mathrm{Ne}\right)$ lacks due to its period $2$.
• In addition, because the valence electrons are so near to the nucleus, a lot of energy would be necessary to excite them to a higher energy level.
• As a result, they have a high electrostatic attraction.

The explanation for incorrect options

• Xenon oxytetrafluoride $\left({\mathrm{XeOF}}_4\right)$, Xenon difluoride $\left({\mathrm{XeF}}_2\right)$ and Xenon hexafluoride $\left({\mathrm{XeF}}_6\right)$ exist.
• Hence, all the other options (A), (C) and (D) are incorrect.

Therefore, the correct option is (B) ${\mathbf{NeF}}_{\mathbf{2}}$.