Polar covalent bonding

Uneven sharing of electrons amongst non-metals
The fluorine has a greater electronegativity than hydrogen so it attracts the electron from hydrogen stronger than hydrogen attracts the electron from fluorine. This causes an uneven sharing of the electrons. The shared electrons spend more time closer to the fluorine atom. This produces a slight negative charge on the fluorine atom and a slight positive charge on the hydrogen atom. These small charges are permanent on the molecule and are referred to as permanent dipoles. They give the molecule slightly positive and slightly negative ends. Permanent dipoles occur when atoms with different electronegativities form covalent bonds. A covalent bond that leads to the formation of a permanent dipole is called a polar covalent bond.

Hydrogen and fluorine atoms react together to share electrons.

Notice how the electrons are unevenly shared and how this causes the molecules to develop permanent dipoles.

The animation above show the formation of instantaneous dipoles in a hydrogen molecule due to the random motion of electrons within the molecule. Notice how temporary these charges are.

 When two identical atoms (with the same electronegativity) combine to form a covalent bond the electrons are shared evenly. Such a covalent bond is called a pure covalent bond. However, even a pure covalent bond can still result in small charges forming on the molecule. Take two hydrogen atoms bonding to form a molecule. The electrons that are shared move randomly between the two atoms under the influence of electrostatic forces. At some point in time, for a small fraction of a millisecond (in other words a very small amount of time indeed) the two electrons may find themselves on one side of the molecule. This results in brief positive and negative dipoles forming on the molecule. Such charges are temporary and disappear as soon as they form. These charges are given the name instantaneous dipoles. As you can well imagine the more electrons you have in a molecule moving randomly the more chance that these instantaneous dipoles will form more often. This is exactly what happens, in that we see more frequent instantaneous dipoles forming in bigger molecules than smaller ones. These instantaneous dipoles create very weak forces of attraction between molecules called dispersion forces.
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Negative chlorine ions are attracted to the anode and form chlorine gas. Positive sodium ions are attracted to the cathode and form sodium metal. Power source Water molecules orient themselves to expose their negative end to the positive ion.Water molecules orient themselves to expose their negative end to the positive ion. Water molecules orient themselves to expose their negative end to the positive ion.Water molecules orient themselves to expose their negative end to the positive ion. Water molecules orient themselves to expose their negative end to the positive ion. Water molecules orient themselves to expose their negative end to the positive ion.Water molecules orient themselves to expose their negative end to the positive ion. The water molecules orient themselves to expose their positive end to the negative ion. The water molecules orient themselves to expose their positive end to the negative ion. The water molecules orient themselves to expose their positive end to the negative ion. The fluorine atom attracts the electrons towards it unevenly and results in this end of the molecule having a slightly negative charge. The fluorine atom attracts the electrons towards it unevenly and results in this end of the hydrogen atom having a slightly positive charge.