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As well as hydrogen bonding with other water molecules, they can also dissolve other molecules such as the lower alcohols with which they can hydrogen bond. But non-polar organic molecules such as hydrocarbons cannot hydrogen bond with water are insoluble & prefer to interact with one another through van der Waals forces.

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Melting & especially boiling points increase with the strength intermolecular bonding. More electrons means more van der Waals forces and this requires more energy to break the bonds.

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At any given time, one part of a molecule might be slightly more positive & the other side negative. These tiny changes influence neighbouring molecules, inducing(creating)the opposite charge in them & creating tiny forces of attraction between molecules. We form instantaneous dipoles or temporary dipoles which are often called van der Waals' forces.

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Bonding pair - a pair of shared electrons that make up a covalent bond
Lone pair - a pair of electrons that don't make up a bond
Strongest repulsion - lone pair-lone pair
- lone pair-bonding pair
Weakest repulsion - bonding pair-bonding pair

Method - predicting shapes of molecules & ions
1. Draw dot & cross
2. List number of bonding pairs & lone pairs
3. Suggest a VSEPR molecule shape
4. Sketch molecule showing bond pairs & lone pairs
5. Apply the sequence for forces of repulsion to fully understand any distortion to the structure

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Valence Shell Electron Pair Repulsion

Groups of electrons around an atom(I.e a pair of electrons in the same orbital) will repel each other & take up positions as far apart as possible. The repulsion between electron pairs are minimised in this way.

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The hydrogen bond is a relatively strong intermolecular bond, having a hydrogen atom joined to a highly electronegative element having lone pairs(fluorine, oxygen, nitrogen). Hydrogen bonding is weak compared to bonding taking place within the atom, but is stronger than van der Waals. In water oxygen has 2 lone pairs & 2 hydrogen atoms, so forms a tetrahedral shape.

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IntERmolecular bonding takes place between molecules & governs properties such as boiling point.
IntRAmolecular bonding takes place within a molecule & governs the internal structure of the molecule.
Forces between molecules(INTERMOLECULAR) are much weaker than covalent bond(INTRAMOLECULAR).

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The ability of an atom to attract electrons in a covalent bond. We can measure the pulling power of different atoms.
The positive difference between the electronegativities of 2 atoms indicates bond polarity.
ΔEN= 0 - pure covalent bonding
ΔEN= 0 to 2.1 - polar covalent(covalent with ionic)
ΔEN= above 2.1 - pure ionic bonding

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Many bonds show an intermediate character between being purely ionic & being purely covalent.
Electron clouds -
Hydrogen chloride is an example of a polar molecule with a dipole, I.e it has a small charge of d⁺ and d- at each end.

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All bonding results from electrical attractions and repulsion between protons and electrons with attractions greater than repulsion.
ATTRACTION -

e- pairs are attracted to the nuclei

opposite spin gives an attractive pair

REPULSION -

Repulsion between the nuclei

Repulsion between pairs of electrons(pairs repel other pairs)

Repulsion between electrons in a pair

Covalent Bonds

The electrons in the pair between the atoms repel one another but this is overcome by their attractions to both nuclei.
If atoms get too close, the nuclei and their inner electrons will repel the other atom giving the bond a certain length.

Ionic Bonds
Cations and anions are arranged so that each cation is surrounded by several anions and vice versa. This maximises attraction and minimises repulsion.
Attractive forces between positive and negative ions are over shorter distances therefore they are stronger.
Repulsive forces between like charges are over longer distances therefore they are weaker.
Repulsions from inner electrons and nuclei prevent the ions from getting too close together.

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Consists of a lattice of positive ions held together by a sea of delocalised electrons given up by each atom.

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Form between metals and non-metals

Form when one atom give one or more electrons to another atom, creating a cation and an anion. The two ions attract one another due to their new charges.

Example of ionic bonding

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Formed between non-metals (or to mak molecules)

Each atom gives an electron to form a bond pair, where each electron has opposed spin.

Example of covalent bonding

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Forms when both electrons forming the bond pair come from the same atom.

We use an arrow coming from the atom supplying the electrons to show these bonds.