Group 13: General trends and Properties
* Group 13 through 18 of the periodic table are called the p-block because the outermost electrons occupy p-orbitals.
* Non-metals and metalloids are located in the p-block, as well as some metals.
* The elements in period 3 and below can have expanded octets by involving d-orbitals in bonding.
* The group 13 elements have 3 valence electrons and have common oxidation states of +3 and +1.
* The group 13 elements show some exceptions to periodic trends of atomic radius, ionization energy and electronegativity.
* Boron is a non-metal, while the other group 13 elements are metals.
* Aluminium compounds have amphoteric properties – it can act as both an acid and a base.
Boron-Compounds
* Borax, Na2B4O7. 10H2O forms alkaline solutions in water.
* The borax bead test can be used to qualitatively identify the presence of transition metals.
* Orthoboric acid, H3BO3 is a weak lewis acid that forms hydrogen bonds.
* Diborane, B2H6 is a colourless, toxic and highly reactive gas.
* Boron forms a tetrahedral borohydride ion, in which the corresponding metal borohydrides act as good reducing agents.
* Boron and boron compounds have a variety of household and industrial uses.
* Aluminium is being highly malleable and a good conductor has a range of industrial uses.
Group 14: General trends and Properties
* All the elements in group 14 have 4 valence electrons.
* All the group 14 elements are solids, with increasing metallic character down the group.
* Germanium and silicon are important semiconductors.
* Common oxidation numbers for the group include +2 and +4.
* Carbon always follows the octet rule, but the other group 14 elements can achieve expanded octets.
* The group 14 elements react with oxygen and halogens. Of the group, only tin reacts with water.
* Carbon can form multiple bonds with itself and other atoms.
* Carbon can form molecules with chains and rings. This is called catenation.
Carbon-Allotropes
* The element, carbon, exists in different allotropic forms.
* Diamond consists of a three-dimensional, rigid lattice of carbon atoms.
* Graphite consists of layers of carbon atoms in sheets of six-membered rings.
* Diamond is extremely hard, but graphite is soft and slippery.
* Buckminsterfullerene contains sixty carbon atoms forming a hollow sphere.
* Graphite is thermodynamically the most stable allotrope of carbon.
Carbon and Silicon Compounds
* Carbon monoxide, CO, is a colourless, odourless poisonous gas.
* Carbon monoxide is a powerful reducing agent used in extracting metals from ores.
* Carbon dioxide, CO2, is a colourless, odourless gas needed for photosynthesis.
* Silicon dioxide, SiO2, or silica, is a network-covalent substance.
* Silicones are organo-silicon polymers.
* Silicates, containing the SiO4-4 anion, are present in glass and cement.
* Zeolites are microporous alumino-silicates.