Bonding

A mixture of 2 or more metals (may also include nonmetals) to improve its properties.

• forms between metals and non-metals • transfer electrons • strong electrostatic forces of attraction • giant lattice • high melting/boiling points • conducts electricity in molten state • mostly soluble in water, but not in organic compounds (e.g. benzene, kerosene)

• only forms between non-metals • sharing electrons • don’t conduct electricity (no free ions) • dissolves in organic solvents, but not in water • low melting/boiling point • held together by weak Van der Waals forces

Extremely large molecules

• giant tetrahedral macromolecular structure • very strong covalent bonds • made up of carbon • each atom has 4 covalent bonds • hardest known substance • atoms can’t slide over each other • bad conductor (no free electrons) • high melting/boiling point (due to the sheer number of bonds)

• layered structure, consists of millions of layers • hexagonal arrangement of carbon atoms • soft substance • high melting/boiling point (due to sheer number of covalent bonds) • can conduct electricity

• metals are electropositive by nature • atoms in a metal contribute their valence electrons to form a sea of electrons • electrons float around the positive metal ions, which are arranged in a regular crystal lattice

The electrostatic attraction between electrons and positive ions in a metal

While both are used to define two or more elements together, in compounds the elements are chemically combined, while in mixtures the elements are just mixed together.