* Covalent bonds involve the sharing of electrons between atoms. This creates a stable molecule where the atoms are tightly bound together.

* Ionic bonds involve the transfer of electrons from one atom to another, creating positively and negatively charged ions that attract each other.

A compound held together by covalent bonds cannot be formed from ions.

Let's look at what happens when a covalent compound dissolves in water:

* Polar covalent compounds like sugar (sucrose) can dissolve in water. This is because water molecules are also polar, with a slightly positive end (hydrogen) and a slightly negative end (oxygen). These opposite charges attract, breaking the bonds between the sugar molecules and allowing them to be surrounded by water molecules.

* Non-polar covalent compounds like oil do not dissolve in water. This is because they have no positive or negative ends to interact with the polar water molecules.

In summary:

* Covalent compounds are formed by sharing electrons, not by the transfer of electrons that creates ions.

* Covalent compounds can dissolve in water, but this is due to interactions with the polar water molecules, not a change in their bonding.

Let me know if you have any other questions!