Structure and bonding

Electrostatic forces (attractions between positive and negative charges) that holds atoms together.

To become more stable by losing, gaining or sharing electrons

Occurs between metal atoms only Metals have little attraction for their outer electrons these electrons are free to move within molecules and considered delocalised The metallic bond is the electrostatic force between the positively charged and delocalised outer electrons

Forms between non-metals Held together by positively charged nucleus and negatively charged shared electrons Two different types - covalent molecular or covalent network

Carbon in the form of diamond or graphite Boron Silicon dioxide

Diamond makes 4 bonds per carbon, is not a conductor and is very strong Graphite makes 3 bonds per carbon, is a conductor and very soft

All consist of single element molecules of differing size The have low melting and boiling points Have low densities Don’t conduct (non metal) Not group 8 They are the diatomic elements or Phosphorus (P4), Sulphur (S8) or carbon in the form of fullerene (C60)

Have full outer shells - noble gases (group 8) Means atoms exist without having to be bonded to one another Weak London dispersion forces hold them together

Formed between metal and non metal element with large differences in electronegativity Non metal gains electron(s) and becomes negative ion Metal loses electron(s) and becomes positive ion. Both positive and negative ion will have same electron arrangement as a noble gas.

They form an ionic lattice