My Science School

               Dmitri Mendeleev had predicted in 1871 that an unnamed element with an atomic number 43 would possibly be present in the universe. He thought it would have properties very close to manganese, and even named it eka-manganese. Nearly seventy years later the element technetium with the atomic number 43 was discovered in a laboratory.

               Many scientists had published reports that they had discovered Mendeleev’s predicted element 43 in 1846, 1847, 1877, 1896, 1908, and 1925. None of these turned out to be technetium, as they all were other elements.

               In 1937, Emilio Segre and Carlo Perrier published the results of their experiment in which they isolated technetium from a sample of molybdenum.

             Technetium was the first element to be produced artificially. All the original technetium present when Earth was formed, has long since decayed.

             Almost the entire element that is produced today is produced artificially. It is so rare an element that only around 18000 tonnes of it could be found in the earth’s crust.

               Today, technetium is used in radioactive isotope medical tests. Highly radioactive, it is also used in a host of diagnostic tests. It has several other industrial and chemical uses too.

               The atomic symbol of Technetium is Tc.

 

 

 

 

 

 

 

 

 

 

 

 

               Molybdenum disulphide, also known as molybdenite is a black, soft mineral which was often mistaken for graphite or lead ore until 1778. Carl Scheele, a German chemist, analyzed the mineral and revealed that it was neither of these substances, and was in fact, a totally new element.

              Molybdenum plays an important role in living organisms. The element is vital for the enzymes in bacteria to undergo nitrogen fixation.

              There are approximately fifty molybdenum-containing enzymes, which are found in both bacteria and animals. Molybdenum is used in the production of many alloys due to its ability to withstand extreme temperatures. Therefore, it is used in the manufacture of military armour, aircraft parts, electrical contacts, industrial motors, and filaments.

              The element is recovered as a by-product of copper or tungsten mining. Molybdenum is not a naturally occurring element; however, it is found in its different states within other minerals.

              Molybdenum is the 54th most commonly occurring element in the earth’s oceans. Russia’s Luna 24 space mission discovered samples of molybdenum on the moon too.

              The atomic number of Molybdenum is 42, and the atomic symbol is Mo.

 

 

 

 

 

 

 

 

 

 

               Niobium has an interesting account of discovery. John Winthrop, an American, located a piece of mineral called columbite in Massachusetts in 1734, and sent it to England for examination. The mineral was analyzed in 1801 by Charles Hatchett, an English chemist. He discovered a new element in the mineral and named it columbium after Columbia, a historical, poetic name that refers to the United States of America.

               William Hyde Wollaston, an English chemist, compared columbite with another mineral, tantalite, and declared that columbium was in fact the element called tantalum. In 1844, Heinrich Rose, a German chemist, working with samples of columbite and tantalite, produced two new separate, but very similar, acids, which he named niobic acid and pelopic acid. Later, he recognized niobium as a distinct element.

               The element is named after Niobe, the daughter of king Tantalus of Greek Mythology. It is shiny-white in colour, and is a soft element. Niobium alloys are used in the production of highly-specialized steel that is used in the manufacture of stronger gas pipelines. Niobium alloys are also used in rocket and jet engines due to their superior strength at extremely high temperatures.

               It has the atomic number 41, and it is represented as Nb.

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               In 1789, a Swedish chemist called Carl Axel Arrhenius made a curious discovery in a quarry of a village called Ytterby. It was a piece of odd-looking black rock. The rock piece contained four elements and one of them was yttrium, named after the village. The village became the namesake of the other elements found in the rock as well, such as, erbium, terbium and ytterbium.

               Yttrium is a soft metal. Yttrium in its pure form is stable in the air when it is a large piece. Whenever yttrium is sliced into little shavings or small particles, it starts to become reactive and thus unstable. About 31 parts-per-million of the earth’s crust is yttrium, and that makes it the 30th most common element. The atomic number of Yttrium is 39, and it is represented as Y.

               The element zirconium is greyish white in colour. In powder form, zirconium is highly flammable. It is not generally found in nature in its metallic form due to the way the element reacts with water. Moon rock samples retrieved by NASA’s Apollo missions found the presence of zirconium in lunar rock.

               Zirconium has the atomic number 40, and it is represented as Zr.

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               Strontian is the name of a village in Scotland. The mineral containing strontium was first discovered in this village, and the element is named after the  village.

               Strontium is a soft, silver-coloured metal. The element has several uses. Strontium blocks X-rays emitted by TV picture tubes. The element is used in paints that glow in the dark. In fireworks, certain brilliant red hues are produced with the help of strontium. It also plays an important role in tracing the origins of species.

               Many scientists have richly contributed to the discovery of strontium. However, it was Humphry Davy who isolated the element for the first time. He achieved the feat in 1808 by means of electrolysis.

               Strontium is the 16th most abundant element in the earth’s crust. It is said that German sugar industry used up to 150,000 tonnes of strontium per year leading up to World War I. Today China is the leading producer of strontium while other countries like Spain, Argentina and Mexico present a stiff competition to the topper. Strontium has the atomic number 38, and it is represented as Sr.

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            Rubidium is a metal which is the 23rd most abundant element found in the crust of the earth. It is silvery-white in colour, and very soft. The element is highly reactive and reacts quickly with air. In nature, there are several minerals which contain up to one per cent of the oxide of rubidium.

            Although rubidium is not a rare metal, it does not have a lot of industrial or commercial uses. Therefore mining of rubidium is fairly limited. It is used mainly for powering atomic clocks in global navigation satellite systems. Sometimes, rubidium is also used in the production of purple colour in fireworks. However, it is mostly used for research.

           Rubidium was discovered by the German chemists Gustav Robert Kirchhoff and Robert Wilhelm Bunsen in 1861. Most often, the element is extracted as a byproduct during the production of potassium or caesium.

            About 0.36 grams of rubidium can be found in the body of an average-sized human. The human body treats rubidium as though it were potassium, so it is most often found within the cellular fluid. Rubidium does not serve a vital purpose in animals and plants.

          The atomic number of rubidium is 37, and the symbol is Rb.

 

 

 

 

 

 

 

 

 

 

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               Anyone who reads comics must have heard of Superman, and the planet he hails from. Superman comes from a fictional planet called Krypton and an imaginary element called kryptonite is his celebrated weakness. Now, our element krypton has nothing to do with either of them. It is one of the rarest gases on Earth.

               Sir William Ramsay, a Scottish chemist, and his student Morris Travers, an English scientist, discovered krypton in 1898. The element has neither colour nor smell. It does not react with any element other than fluorine gas.

               A type of krypton has a line in its atomic spectrum, and it was used as the standard measure of length from 1960. One metre was defined as exactly 1,650,763.73 wavelengths of this line. This continued to be the standard of measurement for 23 years. But, now the definition has changed.

               Since the element is rare, and expensive, its utility is very limited. The gas is often used in incandescent lamps. It extends the life of the tungsten filament that glows in the bulb when the gas is injected into the lamps. The atomic number of krypton is 36, and the symbol is Kr.

 

 

 

 

 

 

 

 

 

 

 

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                    Bromine is a slightly toxic element and in its liquid form can burn your skin.

                    This element is a deep red, oily liquid at room temperature. However, it can quickly evaporate into a gas with the same colour. Bromine has a strong and unpleasant smell too. This element is the only non-metal to exist in liquid form at room temperature.

                    Bromide salts were once a favoured material as flame retardants and sedatives. However, the toxicity of the compound has discouraged people Nom using it.

                   The element is extracted from sea water and natural brines, which is a high concentration solution of salt in water. Bromine is used in the production of fuels, insecticides, fire extinguishers and pharmaceuticals.

                    The mineral deposits of bromine in the US are found in the natural brine wells of Michigan and Arkansas. Israel, Russia, France and Japan are also countries that produce bromine industrially. Worldwide, the production of bromine is estimated to be around 330,000 tonnes per year.

                    Bromine is a harmful element to the atmosphere when exposed in the open. It actively contributes to the depletion of the ozone layer, and lets in the hazardous rays of the sun.

                   It is the 59th most common element in the earth’s crust. Bromine has the atomic number 35, and is represented as Br.

 

 

 

 

 

 

 

 

 

 

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               It is unlikely that you have heard about an element called  selenium. However, it is essential for the human body.

              The element has the ability to block the effects of toxic metals such as arsenic, thallium, and the mercury found in fish. It is also a micronutrient in animals.

              It also plays an important role in the production of several vital enzymes in humans. For healthy joints, heart and eyes, humans need selenium. While it is essential in our body, too much selenium in the diet can be toxic as well.

             Selenium is not a metal, although it may look like one. It is solid in room temperature. Primarily, the element exists in two forms: as solid material in silver colour and powdery form in red colour. The element is a good conductor of electricity. Therefore, it is used in photoelectric cells, photocopiers, solar cells, and semiconductors.

            While Germany is the country that produces selenium the most each year, China is the biggest consumer of the element for industrial purposes. The atomic number of selenium is 34, and the atomic symbol is Se.

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                Do you know that arsenic is called the ‘king of poisons’ and the ‘poison of kings’? It is a very toxic element. From the time of the Roman Empire, all the way to the Victorian era in the 19th century, the element had been used for murder and suicide especially among the aristocrats. History is full of stories of both royalty and commoners carrying out assassination attempts for personal gain using the odourless and tasteless compounds of arsenic. These qualities make it a perfect poison, which can kill anyone quickly if taken too much.

               However, despite its reputation as a lethal substance, arsenic still holds a very important place in the natural world. The element has been used in the medical field for centuries.

              Arsenic is combined with gallium to produce gallium arsenide for use in high speed electronics and optoelectronics. Other applications for arsenic include metal alloys and glass making.

              Arsenic has many allotropes. Allotropes are different structures of the same element. Arsenic was first isolated by Albertus Magnus in 1250. The atomic number of the element is 33, and the atomic symbol is As.

 

 

 

 

 

 

 

 

 

 

 

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               Based on his periodic table, Dmitri Mendeleev, in 1869, had concluded that an element such as germanium really existed. It was, however, Clemens Winkler, a German chemist, who first isolated the element, and proved its existence in 1886. Winkler named the element in honour of his homeland Germany, and called it germanium.

               Germanium is a fairly rare element, and is found in the earth’s crust. It is shiny and silvery in its appearance. It is very hard and brittle. Although there are some minerals that contain a fair amount of germanium like germanite and argyrodite, they are too rare to be mined.

               The element is not a nutrient for organisms in nature. Therefore, its presence in the earth has no significance to plants and animals. However, sometimes germanium is used in medicines.

               Germanium is an important component in semiconductors and fibre optics. Germanium is mostly used in optical systems. Applications such as cameras, fibre optics, and microscopes need this element in their production. The element is also used in infrared optics. It is one of the few elements that expand and turn solid when they are frozen. The atomic number of germanium is 32, and the symbol is Ge.

 

 

 

 

 

 

 

 

 

 

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           Gallium is an interesting metal because it is hard and brittle in a cool atmosphere, soft in standard temperature and liquid in warm conditions. This metal is never found in its free form in nature.

            Dmitri Mendeleev, whom we have seen before as an illustrious scientist and the father of the periodic table, had predicted the existence of gallium before its discovery. He had named the missing element as ‘Eka-Aluminium’.

           The element was first discovered in 1875 by Paul Emile Lecoq de Boisbaudran, a French chemist.

           You may have wondered how LED lights emit such glow. Gallium is used in the Light Emitting Diodes (LED). It is also used in electronic circuits and as semiconductors.

            The element has use in high-temperature thermometers, barometers, pharmaceuticals etc. However, the element has no known biological value.

            Gallium makes up about 0.0019 per cent of the earth’s crust by weight. The largest producers of gallium are Australia, Russia, France and Germany. It has an atomic number of 31, and the symbol is Ga.

 

 

 

 

 

 

 

 

 

 

            Zinc, like copper, is a metal which was in use from ancient times. This bluish-silver coloured metal is crucial to life today as it is important in many industrial processes that often go unseen. Zinc is mostly used as an anti-corrosion agent.

            The element was probably named by the 16th century Swiss physician and alchemist Paracelsus. Zinc is used in the production of brass alloying with copper. There are many other alloys of the metal too. Zinc has non-corrosive properties; and therefore, it is used in plating iron.

             After copper, iron and aluminium, zinc is the most required metal in industry. It is zinc that is used in lithium batteries as anode. It is used in paints, fire safety equipment, wood preservatives, clocks, farming etc.

            The element, in its pure form, was discovered by Andreas Sigismund Marggraf, a German chemist, in 1746. Zinc is the 25th most abundant element in the earth’s crust.

             The element burns with a blue-green flare. Thirty per cent of the production of zinc is done through recycling and the rest by mining. It has an atomic number of 30, and the symbol is Zn.

 

 

 

 

 

 

 

 

 

 

            In ancient times, the metal copper was found in abundance on Cypress, an island country in the Mediterranean.

            The country was a major exporter of the metal to the other parts of the world. It is from Cypress that copper gets its name.

            Copper was the first metal that man attempted to shape and mould. One of the greatest discoveries of the ancient man was the knowledge that a harder alloy metal, bronze, could be produced by adding tin to copper. This discovery led the human race to the Bronze Age.

            Besides gold, copper is the only metal in the periodic table whose colouring is not naturally silver or grey. Shiny and reddish, copper was the first metal that man learned to manipulate, and it remains one of the most important metals in the world today.

            Copper is one of the few metals that occur in nature in their directly useable form. A key metal in industry, copper is used for electrical wiring, plumbing and roofing.

            The atomic number of copper is 29, and the atomic symbol is Cu.

 

 

 

 

 

 

 

 

 

 

 

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               Nickel is a metal which has been in use for thousands of years. Its use by humans dates back to at least 3500 BC. However, the element was discovered quite recently. Axel Fredrik Cronstedt, a Swedish mineralogist, was trying to extract copper from minerals in1751; but succeeded in discovering another metal, which he named nickel.

              Nickel is the sixth most abundant element on Earth. However, its presence in the Earth’s crust is very minimal. The element is 100 per cent more concentrated below the Earth’s surface than in the crust.

             Under standard conditions, nickel is found to be silvery white in colour and is fairly hard. This element is magnetic at room temperature like three other metals, such as iron, cobalt, and gadolinium. However, nickel loses its magnetism above 255 degrees Celsius.

              Most of the metal obtained today is used in the manufacture of nickel steel and alloys. Nickel steel, such as stainless steel, is an extremely strong material. The element is useful for a host of other products such as batteries, coins, guitar strings, and armour plates.

            Nickel is generally identified in meteorites where it is usually found combined with iron. There is a large nickel deposit located in Canada, and scientists think it is from a meteorite that smashed into the Earth thousands of years ago. Atomic number of this element is 28, and the symbol is Ni.