Properties of Solids

molecular solids

made of molecules which are held together by IMF (weak)

properties of molecular solids (4 + eg)

-soft due to weak van Der Waal forces

-most sublime when heated

-low boiling and melting points (usually negative)

-poor conductors of heat, but good insulators

-Eg: I2, F2, Cl2

sublime

change from solid to gas

what makes something a good conductor? (2)

-charged particles

-delocalised particles (usually electrons)

giant atomic solids (2)

-also called macromolecules, or catenising atoms

-there are no discrete/distinct molecules, and therefore have no strong IMF present

catenise

something (atoms) bonding with itself over and over again

diamond (2)

-made of carbon atoms bonded vin a tetrahedral shape

-3D structure forms a lattice

properties of diamond (3)

-hardest natural substance because of its strong carbon bonds and tetrahedral arrangement (non-polar)

-high melting point, indicating very strong bonds

-does not conduct electricity because valence electrons are held in the bonds

graphite (3)

-made up of 1 carbon bonded to 3 other Carbons to make plane forming sheets

-these sheets are held together by London forces (weak)

-4th valence electron is delocalised

properties of graphite (3)

-high melting point because of covalent bonds within the sheets

-soft because of weak London forces holding sheets together, they can move over each other easily

-good conductor of electricity because of delocalised electrons

silicon dioxide (4 + alt name)

-Si has 4 unpaired electrons

-each Si atom bonds with 4 O atoms

-creates a 3D covalent network (similar to diamond)

-very hard and high melting point

-AKA, silica

allotrope

substances of the same element that have different physical structures and properties (Eg: diamond and graphite)

girant ionic solids (3)

-basic units in ionic solids=cations and anions

-held together by ionic bonds

-ionic bonds hold ions in fixed positions in 3d crystal lattices

properties of giant ionic solids (5)

-high melting point due to strong ionic bonds (weaker than covalent in atomic solids)

-hard sue to strong ES forces between ions

-brittle because a strong force can shift ions' positions

-this can cause like charges to near each other and repel=break lattice

-they do not conduct as solids, but do as liquids/solutions as the electrons are ore delocalised

metallic solids (5)

-metals have low ionisation energies (LHS of period) and have empty valence orbitals

-outer shells of atoms overlap, allowing electrons to move between them

-the positive kernel remains in place

-the attraction between the positive kernel and delocalised electron=metallic bond

-many metallic bonds=metallic solid

properties of metallic solids (5)

-moderately high melting point

-high density due to closely packed atoms

-malleable and ductile due to delocalised electrons between layers of kernels

-good conductors as electrons can move freely

-shiny as electrons can get excited by absorbing light, and emit it as they get back to their grounds state

inter particle forces

forces between particles

consist of ionic, covalent, metallic bonds and IMF