Properties of covalent compounds?
Florine and neon :)
Covalent compounds generally have much lower melting and boiling points that ionic compounds. Covalent compounds are soft and squishy. Covalent compounds tend to be more flammable that ionic compounds. Covalent compounds don't conduct electricity in water. Covalent compounds aren't usually very soluble in water.
There are more than two. In general: Covalent compounds have low melting and boiling points while ionic compounds have high melting and boiling points. Ionic compounds are good conductors of electricity when melted, while covalent compounds are not. Ionic compounds are soluble in water, while covalent compounds are soluble in non-polar liquids. These are the essentials, but other differences exist. All of these are generalizations, exceptions do occur.
The properties of covalent compounds are: they have relatively low melting and boiling points, they tend to be soft and relatively flexible, they are more flammable, when dissolved in water they don't conduct electricity, many don't dissolve well in water, and they don't need as much energy to melt or vaporize as an ionic compound does.
It utterly depends. For instance salt (NaCl) behaves nothing like either Sodium or Chlorine, whist FBr (Fluorine and Bromine) has properties similar to Chlorine (ie another halogen). I suspect it depends on the form of bonding: covalent compounds between similar elements, assuming they are not too large, may have similar properties, whilst ionic compounds will not. However, for large covalent compounds like proteins this idea breaks down. In most cases, no.
It is a saturated hydrocarbon. It is a covalent compound and has all properties which are identical to simple covalent compounds. Low boiling and melting points, soluble in organic solvents (most simple covalent compounds are soluble in organic solvent), insoluble in water and does not conduct electricity as in does not have free ions. Its tetrahedral geometry makes it non-polar.