Question

The noble gas xenon forms several compounds (usually involving oxygen or fluorine), but neon, which is also a noble gas, doesn't form compounds. Why? Why couldn't Ne form NeF4 in a similar way to XeF4?

Answer 1

Neon does not form compounds like xenon because neon holds its electrons much more tightly that xenon.

Explanation:

Short answer: Neon holds its electrons too tightly.

Ne is a small atom. Its electrons are close to the nucleus and are tightly held. The ionization energy of Ne is 2087 kJ/mol.

Xe is a large atom. Its electrons are far from the nucleus and are less tightly held. The ionization energy of Xe is 1170 kJ/mol.

So a xenon atom can give up some control of its electrons to a highly electronegative fluorine atom and form XeF₄.

But even fluorine is not strong enough to pull electron density from neon.