Shapes of molecules and ions (6)

When you have a pair of electrons they will repel each other, but will also repel other electron pairs in the molecule so the bonded pairs will position themselves as far apart as possible which gives the molecule a specific shape

Lone pairs will repel a lot more than a bonded pair so they will push the bonded pairs further apart from it and they will be moved closer together

4 bonded pairs, 0 lone pairs 109.5 angle

3 bonded pairs 0 lone pairs 120 angle

2 bonded pairs, 0 lone pairs 180 angle

3 bonded pairs, 1 lone pair 107 angle

2 bonded pairs, 2 lone pairs 104.5 angle

5 bonded pairs, 0 lone pairs 120 and 90 angles

6 bonded pairs, 0 lone pairs 90 angle

3 bonded pairs, 2 lone <90 angle

5 bonded pair, 1 lone pair 90, <90 angle

The ability of an nuclei of an atom in a covalent bond to attract the shared pair of electrons

How big the nuclear charge is and how big the atomic radius is

The Pauling Scale

Fluorine, nitrogen, oxygen and chlorine

If it’s 0 its a pure covalent which means atoms of the same element are bonded together. If it’s 0-1.8 its a polar covalent which means the shared pair of electrons are closer to one atom than the other If it’s more than 1.8 it’s ionic because the shared pair of electrons is a lot closer to one of the atoms than the other until they become accepted by it to form ions.

When the two atoms in a covalent bond are the same or have very similar electronegativities

When both of the atoms have different electronegativity values which means the electronegative atom will have a stronger attraction to the shared pair of electrons and so will create a partially positive and negative dipole.

Water is a polar molecule because O-H is a polar bond. The oxygen is far more electronegative than hydrogen so attracts the pair of electrons and becomes partially negative while hydrogen becomes partially positive. Because water is a non-linear molecule, the two polar bonds don’t cancel.

CO2 is not a polar molecule. This is because even though C=O is polar, the molecule is linear so the dipoles act in opposite directions and get cancelled out.

Because the partial charges on the dipole can attract the ions in the lattice and break it apart. E.g NaCl will dissolve in water because the partially positive H will attract the Cl- and the partially negative O will attract the Na+

Weak interactions between dipoles of different molecules. These could be London forces, permanent dipole-dipole interactions and hydrogen bonding

They are induced dipole-dipole interactions and weak intermolecular forces that occur between all molecules

Electrons are constantly moving around so instantaneous dipoles are being created in molecules. This then triggers instantaneous dipoles in other molecules and they attract each other. In the next instant, the dipole may disappear.