The bond angles, and lengths, of silicon are fairly variable. In carbon they are fairly uniform. IIRC, the difference is because the silicon electrons are further out from the nucleus which reduces the attraction between the electrons and nucleus. This allows the bonds to be pulled around a bit from the tetrahedral shape.

Silicon dioxide isn't bonded with two double covalent bonds, why?

Silicon dioxide has four single covalent bond instead?

Why it can't form that?

"Argon is only known to participate in inter-stitial compounds. It is not involving any chemical change but only a physical change as far as compound formation is concerned. Helium does not form anything. Xenon that way is very nice because of its stable flourides."

 

Summary: Only noble gases that can form a compound with another element are krypton and xenon... ?

"Argon is only known to participate in inter-stitial compounds. It is not involving any chemical change but only a physical change as far as compound formation is concerned. Helium does not form anything. Xenon that way is very nice because of its stable flourides."

 

Summary: Only noble gases that can form a compound with another element are krypton and xenon... ?

 

Yes. Atleast those are the only ones for whom compounds have been synthesized till now. Maybe someone will someday come up with compounds for the other too.

As far as Radon is concerned, its size is favourable to compound formation, though due to its radioactivity, I don't think too many people have tried to make compounds with it. Atleast I have never heard of a Radon compound.

Silicon dioxide isn't bonded with two double covalent bonds' date=' why?

Silicon dioxide has four single covalent bond instead?

Why it can't form that?[/quote']

 

You can generally explain choice of bond formation based on energy considerations. In most probability, energy considerations will explain this too.