Why is water a polar covalent?

Answer 1

In each water molecule oxygen attracts more than its "fair share " of electrons that forms a partial negative charge on oxygen and partial positive charge in hydrogen. So it is polar. Oxygen has more protons than hydrogen, which attract an equal number of electrons. Oxygen and Hydrogen originally bonded to fill their valence shells. Now that the covalent bond is formed, the oxygen "hogs" the electrons.

Answer 2

Water is a polar molecule formed by atoms which have different electronegativities, the atom with the highest level of electronegativity, bonds with the less electronegative atoms. The electronegativity of Oxygen is 3.5 whereas Hydrogen has an electronegativity of 2.20, therefore the difference is 1.4 allowing water to qualify as a polar covalent bond.

Answer 3

Water is covalently bonded, with Oxygen and two Hydrogen atoms each joined to the Oxygen. The Oxygen, however has a "spare" pair of electrons, these negatively charged particles cause attractions between the Oxygen in a first water molecule with the slightly positively charged hydrogens in a second water molecule. This pattern of attraction is repeated so that long loose chains of water molecules build up each mutually attracted to the other via these "Hydrogen bonds". It is this hydrogen bonding which is polar (i.e. plus charge and minus charge) in nature that accounts for water being a liquid at normal temperature and pressure where - for example N2 is a much heavier molecule than H2O and yet is a gas

Answer 4

"Polar-covalent" is how chemists say that the bond in question is not massively polar, ie the bond isn't easily broken when placed in a polar solvent, but nor is the bond completely covalent (more or less equal sharing of bonding electrons between involved atoms). In short, a polar-covalent bond has electrons which spend more time near one atom than another, but not so much that the bond is polar or ionic.

Now for the why: Electronegativity. The difference in electronegativities (EN) between two atoms is a huge factor in determining where the bonding electrons like to spend their time (recall, EN is a measure of "how badly" an atom wants to hold onto electrons when bonded or in a molecule). Oxygen has an EN of about 3.5 and hydrogen about 2.2. Just from this you can see that the oxygen atom is wants electrons more than hydrogen does. The difference here is 1.3. As a general rule of thumb, if the difference in EN's in a particular molecular bond is greater than about 1.5 or 2, the compound is probably ionic. eg for NaCl the difference in EN's is 2.23 (ionic), and for CH4 it's 0.35 (covalent).

Answer 5

Because of the molecular geometry. The shape of the molecule is bent, with the more negatively charged oxygen atom as the central atom, the positive hydrogen atoms on the bottom, and two lone pairs on top. If you draw dipole moment vectors, you will see an overall pull toward the oxygen atom, making it polar.

Answer 6

because they are not metals