Covalent Bonding

How covalent bonds are formed

Electrons are shared between 2 non-metals forming a covalently bonded molecule

The shared electrons are attracted to the nuclei of the atoms forming the bond

Simple molecular substance structure

Consist of covalently bonded molecules held together by van der waals forces

Low melting and boiling point (SMS)

Van der waals forces holding molecules together are very weak and require little energy to overcome

Poor conductors (SMS)

Their structures contain no charged particles

Macromolecular substances

Consist of molecules covalently bonded into a giant lattice structure

Very high melting point (MS)

Each atom has multiple covalent bonds which are very strong and requires a lot of energy to overcome

Rigid

The covalent lattice is very strong

Structure of diamond

Carbon atoms each bonded to 4 other carbon atoms

Diamond is one of the hardest, strongest materials

Structure of graphite

Carbon atoms each bonded to 3 other carbon atoms in flat sheets and non-bonded electrons are free to move between layers

Can conduct electricity and is malleable

Dative bonding

When an atom donates both of the electrons to form a covalent bond

Average bond enthalpy

The strength of a bond

Dative bonds have the same average bond enthalpy as covalent bonds