Dipole Moment in a Lewis Structure

[Jason Slater 3I]

Can someone explain why we draw an arrow to represent the dipole moment in a lewis structure? What does it tell us?

[Chem_Mod]

The arrow points to the delta negative pole in the molecule, the tail of the arrow indicates the delta positive pole of the molecule.

[Katherine_Zhuo_3B]

With the arrow showing us the delta positive pole and delta negative pole, we can determine which atom in the molecule has a higher electronegativity than the other, and will pull the shared electrons closer when sharing.

[William Shu 1G]

Is it just a matter of determining which atom has a higher electronegativity, and then drawing the dipole moment from there?

[Alexandra Watts 3L]

How do we know which is negative and which is positive?

[Noor_Chahal_3G]

The delta negative pole is the atom that is higher in electronegativity.

The delta positive pole is the atom that is lower in electronegativity.

For example in H₂O, oxygen is more electronegative than hydrogen, so oxygen would be delta negative. The 2 hydrogens have a lower electronegativity, so they would be delta positive.