BELLWORK- Determine Shape Draw the Lewis Dot Structure and the 3D structure for ethane (C 2 H 6 ) and ethene (C 2 H 4 ). Do these molecules have any polar bonds?
In review Equal sharing of electrons = covalent LOW electronegativity difference Unequal sharing of electrons = polar MEDIUM electronegativity difference Transfer of electrons = ionic HIGH electronegativity difference
2 bonding domains Three bonding domains Four bonding domains Three bonding and one lone pair Two bonding and two lone pairs
Bond polarity and molecule shape determine if a molecule is polar Bond polarity --- When a bond has a partial negative charge on one atom and a partial positive charge on the other atom. Molecule shape--- the arrangement of atoms in three dimensions (3-D)
A polar molecule has polar bonds and asymmetry Polar bonds Non-polar molecule Symmetry- all sides are the same δ - δ - δ - δ - δ +
A polar molecule has polar bonds and asymmetry Polar bonds Non-polar molecule Symmetry- all sides are the same Polar bonds Polar molecule Asymmetry- has different sides δ - δ - δ - δ - δ - δ + δ + negative side Positive side
If the electrons are not distributed equally, the molecule is polar. The molecule has a negative end and a positive end.
A polar molecule has a partially positive side and a partially negative side. The arrow labels the molecular polarity. It shows that electrons are mostly by the oxygen atom O H H
Polar molecules are affected by electric fields
Polar molecules have two poles; one is partially positive and one is slightly negative. Positive end Negative end N H H H
The positive pole ( + ) is attracted to negative ions and the negative poles( - ) in other polar molecules. POLAR MOLECULES INTERACT!!
+ POLAR MOLECULES INTERACT!! The negative pole ( - ) is attracted to positive ions and the positive poles( + ) in other polar molecules.
Water is a molecule that has two polar O-H bonds.
The electrons are not distributed evenly, so the water molecule is polar. The negative pole is at the oxygen. O is more electronegative than H, so electrons are pulled toward O. Also, there are two lone pairs around oxygen. negative end positive end