My Science School

Silicon, atomic number 14, is a chemical element with the symbol Si. In 1787, Antoine-Laurent de Lavoisier first discovered that this metal was present in rocks. He was a French chemist. In 1800, Sir Humphry Davy mistook silicon to be a compound. Later, in 1811, Joseph Louis Gay-Lussac and Louis Jacques Thénard, two French chemists, prepared impure amorphous silicon by heating potassium with silicon tetrafluoride and named it silicon based on the Latin word silex, which means meteorite.

Silicon has very specific uses. High-purity monocrystalline silicon is a semiconductor material, which can be made to produce solar cells that convert radiation energy into electrical energy. This discovery is highly promising in the development of energy.

Silicon can also be made into cermet composites. These composites are resistant to high temperatures, are very tough, and can be cut. They inherit the advantages of metals and ceramics, and also lack the disadvantages of both, a feature that can be applied in weapons manufacturing and aerospace technologies. Pure silica is also used to manufacture high transparency glass fibre for optical fibre communication.

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Hennig Brandt is often credited for the discovery of phosphorus, and there is a very interesting story behind the discovery of this element. One night, in his laboratory, Brandt was attempting to create the Philosopher’s Stone, an elusive goal that was chased by numerous alchemists from time immemorial. The Philosopher’s Stone is said to transform base metals into gold! The year was 1669.

Brandt was heating a mixture of sand and charcoal with a tar like substance produced by boiling down about 1,200 gallons of urine for over two weeks. He then kept this mixture at the highest temperature his furnace could produce. He had spent most of that day in his laboratory, and after many hours a white vapour formed, which condensed into thick drops. What was exciting was that these drops gleamed brightly for hours. Brandt called this glowing, waxy substance phosphorus, a Latin term for things that give off light. This was a completely new thing to be discovered at that time.

In Brandt’s era, the world was believed to be made up of four elements: fire, air, water, and earth. So, like his colleagues to whom he showed his new compound, Brandt also assumed that it was composed of these elements. (It was only after about a hundred years later that Antoine Lavoisier replaced this worldview with another idea that elements were simple substances, which cannot be further isolated.) Anyhow, Brandt’s phosphorus was a spectacular sight, which is immortalized by Artist Joseph Wright of Derby in his painting The Alchemist.

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Two British chemists, Sir William Ramsay and Morris W. Travers discovered neon in 1898. Ramsay chilled a sample of air until it became a liquid, and he then heated this liquid to capture the gases that boiled off. Over a period of six weeks, Ramsay and Travers isolated the remaining gases in order of abundance; nitrogen, oxygen, and argon were already identified by then.

First, krypton was discovered, but once it was removed, they were left with a gas that produced brilliant red light under spectroscopic discharge. This gas was neon, and it was given its name by Ramsay’s son. The term neon comes from the Greek word novum, which means new.

Neon is the fifth most abundant element in the universe after hydrogen, helium, oxygen, and carbon. It is a noble gas with the atomic number 10. Under standard conditions, it has two third density of air and is colourless, odourless, inert, and monatomic. Large volumes of neon are formed during the alpha capture fusion process that occurs in stars. Neon is also used in lighting, popularly called the ‘neon lights’.

Neon is rarely found on inner terrestrial planets like Mercury, Venus, Earth and Mars because of its highly volatile nature. It is also incapable of forming compounds that can become solids. As neon is lighter than air, it escapes from the Earth’s atmosphere.

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The discovery of sodium is perhaps the most delicious discovery so far. Imagine not having salt in our food! How unappealing it would be!

Sodium is a crucial element that forms common salt or NaCl. Here Na refers to sodium and Cl refers to chlorine, the two atoms that combine to form salt. Although we have used salt for centuries, the scientific discovery of sodium happened only in 1807 as sodium is a highly reactive metal that is hard to isolate.

It was Sir Humphry Davy who discovered sodium (Na) in his laboratory. He used electrolysis to remove it from melted caustic soda and identified that it was a metal. Since pure sodium can cause flames upon reacting with water, Davy had to figure out a moisture-free environment for isolating sodium. In the chemical process of electrolysis, it is the electric currents that create chemical changes.

Sodium is an alkali metal. It is soft and flammable in nature. It appears in a silver-white colour in its pure form. The commonly used compounds such as table salt and baking soda contain sodium. Sodium is an essential element in animals as it regulates a number of body functions.

The English word soda is often considered as the root word from which sodium got its name. The name is also linked to sodanum, a headache remedy, from Medieval Latin. The symbol for sodium on the periodic table, Na, comes from the Latin word ‘natrium,’ which means sodium carbonate.

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The element with atomic number 12 is magnesium. It was discovered by Joseph Black,   Scottish physician and chemist. The metal was discovered in Edinburgh in the year 1755. After its discovery for the first time, many chemists like Thomas Henry and Humphry Davy did further research to enhance the form in which it was found. Magnesium in its pure form was first isolated by Sir Humphry Davy in 1808.

Magnesium was given its name based on the district in Greece where it was found for the first time. Over the years many ground-breaking researches were carried out to study the properties of magnesium. Its discovery has been of great importance and has transformed human life in several ways.

Magnesium is a vital element from the biological angle of plant and animal life. It is a critical element in chlorophyll and helps the plants in photosynthesis. Also, magnesium forms great alloys. When combined with other metals, magnesium enhances the strength and tenacity of the alloy. As a result of this property, it is used in the manufacturing of cars and aeroplanes.

Magnesium also ignites very easily. As a result, it is used in firecrackers. It is one of the most abundant materials on our planet. Its discovery has helped us to produce great advances in the field of science and medicine. Doctors often recommend a magnesium rich diet as it plays an important role in governing various functions of our body.

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In 1772, Daniel Rutherford, a chemist and physician discovered nitrogen when he removed oxygen and carbondioxide from air. He demonstrated that the residual gas from this reaction would not support living organisms or combustion. Carl Wilhelm Scheele and Joseph Priestley were two other scientists working on the same problem, and they called nitrogen “burnt” air or air without oxygen. In 1786, Antoine Laurent de Lavoisier called nitrogen “azote” meaning “lifeless”. All these were based on the observation that nitrogen could not support life on its own.

But nitrogen is extremely essential to life on Earth. It makes up our proteins and can be found in all living systems. Nitrogen gas constitutes 78 per cent of Earth’s air, whereas the atmosphere of Mars only has 2.6 per cent of it. Nitrogen compounds can be found in organic materials, foods, fertilizers, explosives and poisons. Although it makes up a big part of compounds, in excess, nitrogen is harmful to the environment. Nitrogen is named after the Greek word nitre.

Nitrogen is the fifth most abundant element in the universe. It is colourless, odourless and does not mix with other elements easily.

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Over 500 years ago, Leonardo da Vinci suggested that the air we breathe contains something vital to life. He discovered this when he observed that the combustion of air caused animals to suffocate, which meant something was removed from the air in that process. Though many medieval alchemists tried to find what it was, they failed. Then in 1774, Joseph Priestley, an English chemist, separated out the substance and showed that it was a single chemical element, and not some special mix of gases. Priestley also published his findings, becoming the first scientist to do so and thus allowed others to confirm his discovery. This process of documenting is still considered important in claiming priority about discovery disputes.

The French chemist Antoine Lavoisier, who named it oxygen (meaning ‘acid maker’), later claimed that he discovered the gas independently of Priestley. However, it is known that Priestley had already shown Lavoisier how to make oxygen, undermining his claim.

Some historians also argue that the credit for discovering oxygen should go to Carl Scheele, a Swedish chemist, who discovered it several years before Priestley. The sad part is that Scheele’s letter to Lavoisier describing his work never arrived, and his scientific report sat in the printer’s office for two years, all of which led his work to be overshadowed by Priestley’s and Lavoisier’s works.

Oxygen supports life. It is an element with the atomic symbol O and atomic number 8. Pure oxygen is nonflammable and is a colourless, odourless and tasteless gas.

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Fluorine is the most reactive element on the Periodic Table, and it has a violent history in its quest for discovery. Being a vital element for humans and animals, despite its difficult and explosive properties, fluorine is commonly found in drinking water and toothpaste. It is fluorine that helps prevent tooth decay!

Fluorine is the most reactive of all elements. No chemical substance can detach fluorine from any of its compounds. As a result, fluorine does not exist freely in nature and it was extremely difficult for scientists to isolate it. In 1869, George Gore was able to produce a small amount of fluorine through an electrolytic process. But Gore didn’t know that fluorine gas explosively combines with hydrogen gas and in his experiment, the fluorine gas that formed on one electrode combined with the hydrogen gas that formed on the other electrode and exploded. In 1886, a French Chemist named Ferdinand Frederic Henri Moissan was the first to successfully isolate fluorine. His work earned him the Nobel Prize for chemistry in 1906.

According to the Royal Society, fluorine is a vital element in the nuclear energy industry. A small amount of fluorine is essential for maintaining the strength of our bones and teeth, and an excess of it will have the reverse effect of causing osteoporosis or tooth decay. Excess fluorine can also harm the kidneys, nerves, and muscles.

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Lithium gets its name from the Greek word ‘lithos’ which means stone or rock. It was first detected by Johann August Arfvedson in 1817 when he was analyzing petalite ore. Lithium was isolated in its pure form by Humphry Davy, an English Chemist, in the year 1818.

Lithium is a silver-white, soft metal at room temperature. It is the lightest metal and the least dense solid element. Lithium is also highly inflammable, which means it can be stored only in a vacuum, or inert liquids such as purified kerosene or mineral oils. And, because of this, lithium fires are very difficult to put out. If your pour water, it will burn more! Only a powder fire extinguisher should be used.

Lithium is never found in its pure form in nature due to its reactive quality. But it is found as clay or ore in many places such as seawater, mineral springs, and igneous rocks.

We use lithium in many daily objects such as batteries, ceramics and glass. It is also used in lubricating greases, and anti-depression medicines.

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In 1798, mineralogist Rene Just Hauy discovered similarities in the crystal structure and properties of beryl and emerald, and this led to the discovery of the element beryllium. Its atomic number is 4.

Beryl, a mineral, appears in different colours. For instance, Emerald, a variety of beryl, is green in colour. This made Hauy wonder if these two minerals have something in common. He approached Nicolas Loius Vaunquelin, a French chemist who specialized in the analysis of minerals, and he discovered a new sweet-tasting substance in them both. This substance is now called beryllia, BeO.

Beryllium was isolated from its salts in 1828 by Friederich Wohler in Germany and by Antonie Bussy in France, independently. It is the 44th most abundant element on Earth and has two-thirds the density of aluminium. It is a non-magnetic element and is used in nuclear reactors as a reflector and absorber of neutrons. Due to their lightweight nature, beryllium alloys are used in the aerospace industry for high-performance aircraft, satellites and spacecraft. Beryllium-copper alloy also makes spark-proof tools. The United States, China, and Kazakhstan are the only countries that process beryllium ores into high-performance products.

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The element whose atomic number is 5 is called boron. It was partially isolated by Joseph L. Gay-Lussac and L. J. Thenard, two French Scientists and independently by Sir Humphry Davy in London. Gay-Lussac and Thenard made boron by reacting boric acid with magnesium and sodium. Boron was yielded as a grey solid. They named it bore as they thought it shared its characteristics with sulphur and phosphorous.

Sir Humphry Davy tried to produce boron by the electrolysis of boric acid first, but he was not satisfied with the results. Later, he reacted boric acid with potassium in a hydrogen atmosphere, which produced a powdery substance. Davy commented that this substance was ‘of the darkest shades of olive’, was of unknown origin or very dark, very friable, and that it does not scratch glass. But the truth was, none of these scientists had produced pure boron. Their samples were only 60 per cent pure. It was only in 1909 that 99 per cent pure boron was produced by distilling boron halides with hydrogen. This was done by an American chemist named Ezekiel Weintraub.

Compounds of boron such as borax (sodium tetraborate) were known and used by ancient cultures for thousands of years. Borax is named after the Arabic word buraq, which means white.

Boron is very hard, toxic and resistant to heat. It is an essential nutrient for all green plants. Being an excellent neutron absorber, it is used to control nuclear reactions. When made into an alloy with steel, or combined with carbon, titanium or zirconium, boron becomes excellent control rods for nuclear reactors. Boron compounds burn with a green flame, which leads to their use in fireworks.

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Helios, the root word from which helium was derived, refers to the Sun in Greek. This goes back to the observation of the yellow spectral lines that were given out by the chromosphere of the Sun on August 18th, 1868. Initially, Jules Janssen, the French astronomer who was studying it thought that it was caused by the element sodium. But on October 20th of the same year, an English astronomer named Norman Lockyer observed the same lines and concluded that this was caused by some other element in the Sun and named those lines as D3 Fraunhofer lines. Later, Lockyer and Edward Frankland, an English chemist, named the element as helium. The atomic number of helium is 2.

Though helium was thought to be present only in the Sun, in 1882, Italian physicist Luigi Palmieri detected it on Earth when he was analyzing the lava from Mount Vesuvius volcano. But helium was successfully isolated by Sir William Ramsay, a British chemist, while he was searching for argon. He isolated it by treating a sample of cleveite with mineral acids, and it was confirmed by Sir William Crookes and Sir Norman Lockyer. Consequently, a number of interesting properties of helium were discovered, such as the discovery that an alpha particle is actually a helium ion. This happened in 1907 through the works of Ernest Rutherford and Thomas Royds. Later, in 1908, helium gas was first liquefied by cooling it to less than one Kelvin by Heike Kamerlingh Onnes, a Dutch physicist.

In today’s world, helium is used in many industrial, commercial and recreational activities. Being lighter than air, it is used in airships and balloons to provide buoyancy during flight. It is also preferred in airships as it is non-inflammable and also fire-retarding. Helium is also used in MRI scanners and spectrometers as a coolant for the superconducting magnets in them.

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Elements are the building blocks of our world. They are the most basic form of a substance and are created by different combinations of protons, neutrons, and electrons. The combination of these different elements forms compounds. Humans discovered and started using various elements in the early societies. Back then people did not know their chemistry, but nevertheless, began using elements like carbon, copper, and gold.

Though many attempts were made to classify and tabulate these elements, the modern understanding of the nature of elements evolved from the work of a Russian Chemist, Dmitri Mendeleev. He published the first recognizable periodic table in 1869 based on atomic mass.

The present periodic table lists and arranges elements in the order of their atomic number. There are rows and columns in it. The vertical column in the table is known as a group, while the horizontal row is called a period. These groups are assigned numbers, and some of these groups have accepted names. For example, elements of group 17 are known as halogens; and number 18 is the group of noble gases.

By November 2016, the International Union of Pure and Applied Chemistry had recognised 118 elements. Of these, the first 94 occur naturally on Earth, and the other 24 are produced in nuclear reactions. Except for the radioactive elements, almost all other elements are available for scientific and industrial purposes in varying quantities.

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Though scientists had produced and used hydrogen for many years, it was much later that it was discovered as an element. Robert Boyle, an Irish natural philosopher, is said to have produced hydrogen as early as 1671. But it was in 1776 that the British scientist, Henry Cavendish confirmed that hydrogen was a particular element. He called it ‘inflammable air’ and described its density as well. Later, Antoine Lavoisier conducted experiments similar to Cavendish and gave the element its name, hydrogen.

Hydrogen is the simplest and the most common element, which is present in almost all matter. Unlike other atoms, hydrogen has only one electron and one proton. It does not have a neutron in its atom. Hydrogen is also the most abundant element in the universe. It makes up about three-quarters of all matter.

One of the most important properties of hydrogen is that it is highly flammable, which means that it will burst into flames very quickly. This makes it extremely dangerous as well as very useful. In fact, the stars in our universe shine bright because the hydrogen in them is being burned. This process is called fusion. It is being studied to see if we humans can use it as a source of power. Our sun has enough hydrogen to last another 5 billion years!

Hydrogen is also a very important commercial element. Liquid hydrogen is used to study superconductors and it is also an excellent rocket fuel when combined with liquid oxygen. Another important use of hydrogen is in the Haber process, where it is combined with nitrogen to produce ammonia, a compound used to manufacture fertilizers, refrigerants, dyes etc.

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