Bonding, structure, and the properties of matter

Ionic compounds

- metal and nonmetal

- joined together by acttractions between positively and negatively charged ions

- giant lattice

- very strong electrostatic bonds

- very high melting and boiling points as it takes a lot of energy to break bonds

- dissolve in water as water molecules are able to separate ions but retain shape

- if in liquid form the ions are able to move and carry charge (conducts electricity)

Properties of small/simple covalent molecules

- strong covalent bonds between atoms

- attractions between molecules are very weak

- very low melting points as little energy is required to break attractions (usually gases or lquids at room temp)

- don't conduct electricity because all the electrons are used up in covalent bonds so there are no free electrons that can move around or carry charge

- when melted weak forces between molecules break not strong bonds between atoms

Polymers

- long chain of small molecules that have been joined together

- joined to other chains with weak intermolecular forces

- ther larger the molecule, the higher the boiling point because it takes a lot of energy to break the forces between the molecules

-usually solid

Diamond (carbon), Graphite, Silicon Dioxide

- millions of atoms

- shared pair of electrons

- very high melting and boiling points

- do not conduct electricity (except graphite)

Metals and Alloys

- giant structures

- atoms held together by strong metallic bonds

- high melting and boiling points

- maleable and ductile (layers can slide past eachother)

- pure metals too soft, so are made into alloys (mixture of metals), which are harder, by disrupting the layers, making them unable to move

- both are good conductors of heat and electricity because thermal and electrical energy can be carried by sea of delocalised electrons that hold atoms together

Allotropes of Carbon

Diamond

- strong covalent bonds

- one carbon bonds to four carbons

- very hard

- very high melting point

- doesn't conduct electricity (electrons fixed in the covalent bonds so can't carry charge)

Allotropes of Carbon

Graphite

- arranged in hexagonal layers (interconnected with other hexagons)

- strong covalent bonds

- each carbon atom connects to three other ones (fourth electron becomes delocalised (conducting electricity as able to move and carry charge)

- delocalised electrons mean bonds between layers aren't as strong (weak intermolecular forces)

- very high melting point

- soft because each layer can slide past eachother

- a chemical bond is an electrostatic attraction between a positive and negative particle.

- an ionic bond is an electrostatic attraction between oppositely charged ions.

- positive ions (cation): formed from metal atoms as they lose electrons

- negative ions (anion): formed from non metal atoms as they gain electrons

- giant ionic lattice

- multidirctional bonding