1. principles of chemistry

+ some energetics

ionic bonding

electrostatic attraction between two oppositely charged ions

covalent bonding

formed between two non-metal atoms by sharing a pair of electrons to fill in the outer shell

ionic lattices

strong electrostatic forces between oppsitely charged ions, cannot conduct unless molten and in aqueous solution - solid: fixed position, with regular repeating pattern

giant covalent lattices

• do not conduct except graphite

• insoluble

• high melting and boling points

diamond

• each carbon atom joined to 4 other carbon atoms

graphite

giant structure; each carbon is covalently bonded to 3 other carbons, forming layers of hexagonal rings,

• conduct electricity because each carbon atom bonded to 3 other carbon atoms

• weak IMFs between layers

C60

SIMPLE molecular structure (not giant like graphite and diamond)

• weak intermolecular forces of attraction between them which take little energy to overcome. Hence C₆₀ fullerene has a low melting point, and it is soft

• covalently bonded to 3 others and the other electrons are delocalised, these electrons cannot jump between different molecules.

isotope

atoms of the same element with different masses

why ionic lattice has high melting point

• attraction between ions is strong

• lattice

• lots of energy required to overcome attraction

compound

substance containing elements bonded together

how atoms held together in covalents

shared pair of electrons attracted to both nuclei

how increasing temperature affects the rate of reaction

• the rate of reaction increases

• because the particles gain (kinetic) energy

• more collisions per unit time

• more of the collisions are successful