Covalent Bonding

Sharing electrons, only in their outer shell

Having a full outer shell gives them the electronic structure of a noble gas

Form very strong covalent bonds

Weak intermolecular forces so the melting and boilibng points are very low

Don't conduct electricity because there are no ions so no electrical charge

Macromolecules

No charged ions - doesn't conduct electricity

All atoms bonded to each other by strong covalent bonds so have a very high melting and boiling point

Diamond

• forms four covalent bonds in a rigid giant covalent structure
• makes it the hardest natural substance

Graphite

• each carbon atom forms 3 covalent bonds
• this creates layers which are free to slide over each other, so graphite is soft and slippery
• layers held together losely so can be rubbed off because of teh weak intermolecular forces
• only non metal which is a good conductor of heat and electricity. each carbon atom has one delocalised electron