Topic 2 - Bonding

A strong electrostatic force of attraction between oppositely charged ions in a lattice

When atoms share or transfer electrons to achieve a more stable electron arrangement, often a full outer main level of electrons.

SO4 (2-)

NO3 (-)

OH (-)

CO3 (2-)

NH4 (+)

Always solid at room temp Giant structures = high melting points Only conducts when molten or in aqueous solution as ions are not free when solid

Strong electrostatic force of attraction between positive metal ions and sea of delocalised electrons

Giant metallic lattice

Good conductors of electricity as delocalised electrons can move throughout the structure. High thermal conductivity due to delocalised electrons and the closely packed ions allowing vigorous vibrations. Malleable and Ductile - arranged in layers which can slide and each metal ion will still be in the same environment. High melting points

Charge on the ion - bigger charge = more delocalised electrons and the strong the force of attraction between electrons and metal ions. Size of the ion - Smaller ion means the closer the electrons are to the positive nucleus = stronger bond

A strong electrostatic force of attraction between positive nuclei of the atoms involved and the shared pair of electrons

A single covalent bond contains one pair of shared electrons Multiple covalent bonds contain multiple shared pairs

A co-ordinate (dative covalent) bond contains a shared pair of electrons with both electrons supplied by one atom.

High as lots of energy is required to overcome the strong electrostatic forces of attraction between oppositely charged ions.

Macromolecular

Each carbon strongly, covalently bonded to 4 other carbons in a giant lattice of atoms which are arranged tetrahedrally. High melting and boiling Does not conduct electricity as there are no freely moving charged particles Very hard as strong covalent bonds hold atoms in fixed positions

Each carbon atom strongly, covalently bonded to 3 others forming a giant lattice of atoms in a trigonal planar arrangement. High melting and boiling point Does conduct electricity as between layers there are delocalised electrons that can move freely and conduct - can only conduct electricity along hexagonal planes and not vertically throughout the structure. Soft and slippery as there are weak forces of attraction (VDW forces) between the layers which are easily overcome to allow the layers to slide relative to one another

Directly proportional to the mean kinetic energy of the particles

As some of the KE is used to overcome the forces of attraction between particles to allow them to escape. The leads to a lower mean KE and therefore a lower T

Particles vibrate faster KE + T increase

Heat energy is used to overcome or partially overcome the forces of attraction between particles instead of increasing the KE. Therefore T is constant through melting. As KE remains constant

Heat energy is used to overcome the forces or bonds between the particles rather than increase the KE. Liquid boils but KE remains constant so T remains constant