Chemistry

Metallic structures are conductive in the solid and molten state because their sea of electrons are free to move about throughout the lattice, so when a voltage is applied, the electrons can move towards the positive terminal.

The bonding between the metal ions and the sea of electrons is non-directional, meaning the individual ions can move in relation to each other, without the bonds breaking.

Strong attractive forces between the ions and sea of electrons hold the lattice structure together. As a result high temperatures are needed to disrupt the lattice.

Occurs between metallic elements and non-metallic elements, called salts. The metal loses its valence electrons to become stable, and gives them to the non-metal to complete it’s valence shell. This forms lattice structures because of the high electrostatic forces between the positive and negative ions.

They don’t conduct electricity in the solid phase because the ions are tightly held together within the lattice, so they can’t carry a charge. They also don’t have mobile electrons to carry a charge.

They conduct electricity when molten because the ions are mobile and carry a charge.

They are conductive in aqueous solutions because the ions are free and carry charge so therefore can conduct electricity.

If a force is applied to the ionic lattice, layers of ions will align alongside each other, meaning like charges will be aligned, so the repulsive forces will break apart the lattice.

Ionic bonds are strong electrostatic forces between ions, meaning lots of energy is needed to break apart the bonds.

Occurs when non-metal elements bond to other non-metal elements. The valence electrons are shared between the bonded atoms so each atom achieves a full valence shell. A covalent bond is directional.

Small groups of atoms become covalently bonded to each other, forming molecules.

IntRAmolecular forces are the strong covalent bonds within the molecule, while intERmolecular forces are weak forces that allows weak attraction between molecules.

The electrons are localized within each atom’s electron cloud, or shared in a bond, and none of the atoms are ions, meaning charge can’t be carried.

Acids or bases react with water (ionize) forming ions that can carry a charge.

Only weak intermolecular forces occur between molecules, hence they can be easily separated making the substances soft and weak.

The weak intermolecular forces are easily overcome with heat energy, yet the intramolecular forces are unaffected.

A continuous array of covalently bonded atoms, with stong bonds throughout the substance.

Electrons are held in fixed positions and can therefore not move and carry charge or heat. Graphite is an exeption as it has delocalised electrons between its layers.

Due to strong covalent bonds, the array is difficult to disrupt. Graphite is an exception because it has strongly bonded flat 2D layers, yet weak bonding between the layers.

Have very strong bonds between all the atoms in the structure.

Each carbon atom is bonded to four neighbouring carbon atoms in a 3D array.

Allotropic form of carbon. Consists of 60 carbon atoms bonded in a cage structure.