Group 13-16: Post Transitional Metals, Metalloids and Nonmetal
Updated: Oct 3, 2020
Post Transition Metals:
They are also called as poor metals or other metals.
Aluminum(Al):
It is a silvery and ductile member of the poor metal group of elements, aluminum is found primarily as the ore bauxite. Although aluminum is the most abundant metal in the earth's crust, it is never found free in nature. All of the earth's aluminum has combined with other elements to form compounds. Two of the most common compounds are alum, such as potassium aluminum sulfate (KAl(SO4)2·12H2O), and aluminum oxide (Al2O3).
Physical properties:
Aluminum has low density. hence a soft and lightweight metal.
It is ductility (which allows it to be stretched into a wire), and malleability (which means it can be easily formed into a thin sheet).
Chemical properties:
It has a dull silvery appearance, because of a thin layer of oxidation that forms quickly when it is exposed to air.
Aluminum is nontoxic (as the metal).
It is nonmagnetic and non-sparking.
It is an excellent conductor of electricity and heat.
Occurrence:
Aluminum is one of the most widely used metals and also one of the most frequently found compounds in the earth's crust. It is generally found on Earth in minerals and compounds such as feldspar, beryl, cryolite, and turquoise. The ore bauxite contains large amounts of aluminum oxide. Modern processes allow for aluminum to be obtained from bauxite fairly cheaply which makes the metal to be used in a number of applications.
Uses:
Aluminum is combined with other elements such as copper, zinc, silicon, and magnesium to form alloy. These are used in the manufacture of soda cans, automobile parts, bicycles, aluminum foil, power lines, siding for houses, and even baseball bats.
Aluminum compounds includes aluminum sulfate It is used for water treatment.
Aluminum oxide is used as a reagent in various industrial processes.
Aluminum chloride is used in refining petroleum.
Discovery:
Chemist Hans Christian Orsted first produced a metal he thought was aluminum in 1825 and suggested that it was a new element. Credit is also given to Friedrich Wohler for first isolating the element in 1827. Aluminum gets its name by sir Humphry Davy, from the mineral alum, which gets its name from the Latin word "alumen" meaning "bitter salt."
Fascinating facts:
Aluminum has only one naturally occurring isotope, aluminium-27, which is not radioactive. Hence it is found in compounds only not as a free element.
Aluminum is 100% recyclable and maintains the same physical properties after recycling as the original aluminum.
When it is exposed to the air, a thin layer of aluminum oxide is formed on the surface of the metal. This prevents further corrosion and rusting.
Gallium(Ga):
Pure gallium has a stunning silvery color. Gallium is solid at normal room temperatures, but it becomes liquid when heated slightly. Gallium atoms have 31 electrons and 31 protons with 3 valence electrons in the outer shell.
Physical properties:
It is stunning silver metal.
Solid gallium is soft enough to be cut with a knife.
Chemical properties:
It is stable in air and water; but it reacts with and dissolves in acids and alkalis.
It has low melting point and high boiling point.
It has one of the widest liquid ranges of any element.
Occurrence:
Gallium does not exist in pure form in nature, and gallium compounds are not a primary source of extraction. it tends to be widely dispersed. Several ores, such as the aluminum ore bauxite, contain small amount of gallium, and coal may have a relatively high gallium content. Most gallium is produced as a byproduct of mining other metals including aluminum (bauxite) and zinc (sphalerite).
Uses:
It forms a bright, highly reflective surface when coated on glass. It can be used to create brilliant mirrors.
Gallium easily alloys with most metals, so it is used to form low-melting alloys.
Analog integrated circuits are the most common application for gallium, with optoelectronic devices (mostly laser diodes and light-emitting diodes) as the second largest end use.
Gallium has semiconductor properties, especially as gallium arsendite (GaAs). This can convert electricity to light and is used in light emitting diodes (LEDs) for electronic display and watches.
Gallium is used in some high temperature thermometers.
Discovery:
Gallium was first predicted by Russian chemist Dmitri Mendeleev. However, it was French chemist Paul Emile Lecoq de Boisbaudran who first isolated the element in 1875 and is given credit for its discovery.Gallium gets its name from the Latin word "Gallia" for "France" in honor of its discoverer's home country.
Fascinating facts :
Gallium based solar panels are used to provide power for space applications like satellites
It is used to make bright blue LEDs.
Large amounts of gallium are used at the Neutrino Observatory in Italy where it is used to study solar neutrinos produced inside the Sun.
Indium(In):
Indium is a soft, ductile, malleable, lustrous metallic metal. Its color is silvery white and it has a face-centered tetragonal structure. It is liquid over a wide range of temperatures, like gallium that belongs to its same group. Both indium and gallium are able to wet glass.
Physical properties:
Indium is a soft, ductile, malleable, lustrous metallic metal.
Its color is silvery white .
Chemical properties:
Indium is stable in air and in water but dissolves in acids.
When heated above its melting point it ignites burning with a violet flame.
Occurrence:
Indium is not widely dispersed in the environment. Cultivated soils are reported to be richer in indium than non cultivate. Indium produced in industry comes as the by-product of smelting zinc and lead sulfide ores, some of which can contain 1% indium. World production comes mainly from Canada and is around 75 tonnes per year, reserves of the metal are estimated to exceed 1500 tonnes.
Uses:
Indium is used in low-melting fusible alloys.
it is used as a protective plate for bearings and other metal surfaces.
It can be used to form corrosion-resistant mirror surface.
Indium foils are used to assess what is going on inside nuclear reactors.
It is used as light filter in low pressure sodium vapor lamps.
Discovery:
Indium was discovered by the German chemists Ferdinand Reich and Hieronymus Theodor Richter in 1863. while looking for traces of the element thallium in samples of zinc ores they found a brilliant indigo line of indium in the sample's spectrum.
Fascinating facts:
Indium can be scratched with a fingernail and bent into any shape.
It is used to coat the bearings of high speed motors since it allows for the even distribution of lubricating oil.
Tin(Sn):
Tin is not easily oxidized and resists corrosion because it is protected by an oxide film. Tin resists corrosion from distilled sea and soft tap water, This allows it to be used as a plating material to protect other metals and can be attacked by strong acids, alkalis and acid salts.
Physical properties:
Tin is a soft silvery-gray metal.
It is very malleable (meaning can be converted into a thin sheet).
It can be polished to a shine.
Chemical properties:
Tin resists corrosion from distilled sea and soft tap water.
It can be attacked by strong acids, alkalis and acid salts.
Occurence:
Tin is generally not found in its free form. It is found in the Earth's crust primarily in the ore cassiterite. It is around the 50th most abundant element in the Earth's crust. The majority of tin is mined in China, Malaysia, Peru, and Indonesia.
Uses:
Tin-plated steel containers are widely used for food preservation.
Tin alloys are employed in many ways: as solder for joining pipes or electric circuits, pewter, bell metal, babbit metal and dental amalgams.
The niobium-tin alloy is used for superconductiong magnets.
Tin oxide is used for ceramics and in gas sensors (as it absorbs a gas its electrical conmductivity increases and this can be monitored).
Tin foil was once a common wrapping material for foods and drugs, now replaced by the use of aluminium foil.
Discovery:
Tin gets its name from the Anglo-Saxon language. The symbol "Sn" comes from the Latin word for tin, "stannum." It has been known about since ancient times. Tin was first heavily used starting with the Bronze Age when tin was combined with copper to make the alloy bronze. Bronze was harder than pure copper and was easier to work with and cast.
Fascinating facts:
Tin can form two different allotropes under normal pressure. These are white tin and gray tin. White tin is the metallic form of tin we are most familiar with. Gray tin is non-metallic and is a gray powdery material. There are few uses for gray tin. White tin will transform into gray tin when the temperature falls below 13.2 degrees C. This is prevented by adding small impurities to white tin.
Bronze typically consists of 88% copper and 12% tin.
Thallium(Tl):
Thallium is very soft and malleable. It can be cut with a knife. If left in air, a heavy oxide builds up on thallium and the hydroxide is formed in the presence of water .
Physical properties:
Thallium is very soft silver grey lustrous metal.
The metal is very soft and malleable. It can be cut with a knife.
Chemical properties:
If left in air, a heavy oxide builds up on thallium.
It forms the hydroxide in the presence of water.
Thallium salts are used as reagents in chemical research.
Occurrence:
Thallium element and its compounds are toxic and should be handled carefully.
Thallium occurs in the environment naturally in small amounts. Thallium is found as a mineral in the elements crooksite, lorandite and hutchinsonite. It's also found as a trace element in iron pyrite and obtained from this ore by roasting the mineral. Small amounts of thallium are found in manganese nodules on the ocean floor.
Uses:
Thallium is used for making low-melting point special glass for highly reflective lenses.
Thallium salts are used as reagents in chemical research.
Thallium sulfate is still sold in developing countries where it is still permitted as a pesticide, although banned in Western countries.
Since its electrical conductivity changes with exposure to infrared light, it is used in photocells.
It is used for sink-float separation of minerals.
Thallium amalgam is used in thermometers for low temperature, because it freezes at -58 °C (pure mercury freezes at -38 °C).
Discovery:
British chemist William Crookes discovered thallium spectroscopically in 1861. Both Crookes and French chemist Claude Auguste Lamy isolated the element in 1862 independently. Thallium was named after the Greek word thallos, meaning green shoot or twig. It was named after its green spectral line.
Fascinating facts:
Thallium is the most toxic element on the periodic table in it's natural form.
Thallium was used as rat and ant poison in the United States until 1975, when it was banned because it started poisoning children and babies as well.
Lead(Pb):
Lead is a very heavy element.Under standard conditions lead is a soft slate grey metal with a bluish tint. It becomes a darker gray after coming into contact with air. It is very malleable (can form a thin sheet) and ductile (can be stretched into a long wire). Lead is a poor electrical conductor when compared to other metals.