Water, or H2O, is an Covalent compound.
It's an ionic bond.
its polar
Neither. Radiation is energy, and not made of matter.
Not all ionic salts dissolve in water, just most of them. Anyways, most molecular substances don't dissolve in water because they are more stable not dissolved. This is partly due to the fact that...
Figure: http://www.kemi.fi/lukio/yo/kuvat/00s1.gif The watermolecules break the ionic bonds and form aquaions.