Question

becuase oxygen is more electrongative than hydrogen, the water molecul is

Answer 1

Due to the difference in electro-negativities between the oxygen and hydrogen the bonding between the two atoms is polar covalent. This means an unequal sharing of the electrons. The oxygen is more electronegative so hence it is more greedy in pulling the shared electrons between the atoms closer to itself. This leaves the hydrogen atoms in water slightly electron deficient whilst the oxygen is electron rich. The result is an overall dipole moment in water. one can consider each bond to have a dipole moment and as such to act as a connection point to associate with other dipoles (water molecules). The association of different water molecules through the dipoles is often called hydrogen bonding and this can result in a multitude of structures from chains to tetrahedral arrangements. This unique property is responsible for the higher than expected boiling/melting point of water as well as the expansion in volume of ice and hence the lower density of ice relative to liquid water.