Tnpsc Annual Planner 2023 To 2024

Highlights of Annual Planner 2023

Upcoming TNPSC Exams 2023 Vacancies Exam Date
Road Inspector In Rural Development And Panchayat Raj Department 762 May 2023
TNPSC Group 1 32 November 2023
Combined Engineering Services Examination 101 December 2023
Group 4 and VAO Exam 8000 February 2024

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Which degree is best for Tnpsc Group 1?

TNPSC Group 1 Preferential Qualification

Name of the Post Preferential Qualification
Assistant Commissioner (Commercial Taxes) Second Preference Degree both in Commerce and Law.
Third Preference Degree either in Commerce or Law together with a Diploma in Taxation laws.
Fourth Preference Degree either in Commerce or Law.

What is Group 1 exam in Tamilnadu?

TNPSC Group 1 Notification – TNPSC Group 1 Notification 2023: The TNPSC Group 1 Notification for 2023 will be released by the Tamil Nadu Public Service Commission. The notification will contain all the important details such as the eligibility criteria, examination pattern, syllabus, important dates, and other important information for the TNPSC Group 1 examination.

TNPSC Group 1 Notification 2023 Overview
Exam Name TNPSC Group 1 Recruitment
Category TN Govt Jobs 2023
TNPSC Group 1 Posts Various
TNPSC Group 1 Recruitment 2023 Notification To be released
TNPSC Group 1 Vacancy 2023 To be released
TNPSC Group 1 Notification To be announced
TNPSC Group 1 Age Limit 21-39 years (as per the post)
TNPSC Group 1 Qualification Graduation in any stream
TNPSC Group 1 Selection Process Prelims, Mains, Interview
TNPSC Group 1 Salary Rs.56,100-2,05,700/-
Official Website

What is the salary of DSP in Tamilnadu?

TNPSC Group 1 Salary 2022

Deputy Superintendent of Police Grade Pay-5400, Level 22, PB-3 (15600 to 39100)
Assistant Commissioner Grade Pay-5400, Level 22, PB-3 (15600 to 39100)
Deputy Registrar of Co-operative Societies Grade Pay-5400, Level 22, PB-3 (15600 to 39100)

Which degree is best for Group 2?

A Master’s Degree in Commerce or Economics or Statistics or A Bachelor’s Degree in Commerce or Economics or Statistics with a pass in the final examination of the ICWAI.

What is the salary of Group 1 officer in Tamil Nadu?

TNPSC Group 1 Salary – There are several posts that the aspirant can apply to. Let’s look into the job profile and pay structure of various posts under TNPSC Group 1. The pay structure for the TNPSC group 1 post in Level 22 is Rs.56100- 177500. This is the revised scale.

The Deputy Collector is employed under the Tamil Nadu Civil Service. The Deputy Superintendent of Police is employed under the Tamil Nadu Police Service. The Assistant Commissioner is employed in the Tamil Nadu Commercial Taxes Service.The next post is of the Deputy Registrar of Co-operative Societies under the Tamil Nadu Co-operative Service.The Assistant Director of Rural Development is a post under the Tamil Nadu Panchayat Development Service.The District Officer (Fire and Rescue Services) is under the Tamil Nadu Fire and Rescue Services.

While the above are the main posts under the TNPSC group 1 list, the group 1 post is further divided into a technical and a non-technical group. So the candidate can have more clarity on the kind of post and then apply for the posting as per their interests.,

What is the highest salary in government job in Tamil Nadu?

The highest-paying job at Government Of Tamilnadu is a Joint Director with a salary of ₹18.5 Lakhs per year. The top 10% of employees earn more than ₹12 lakhs per year. The top 1% earn more than a whopping ₹35.59 lakhs per year.

Are Group 1 hard?

Aims of this page – After studying this page, you should be able to:

recall physical properties of the alkali metalsdescribe the reactions of lithium, sodium and potassium with waterdescribe and explain the pattern in reactivity of lithium, sodium and potassiumpredict the reactivity of other alkali metals.

The group 1 elements are placed on the left of the periodic table. They are called the alkali metals because they are metals, and their oxides and hydroxides form alkaline solutions. In general, the alkali metals:

are soft, and easily cut with a knifehave relatively low melting points compared to other metals.

You need to know details about the first three alkali metals (lithium, sodium and potassium). Rubidium, caesium and francium are the other alkali metals. Sir Humphry Davy was the first person to isolate sodium and potassium. He used the electrolysis of molten sodium hydroxide and potassium hydroxide to do this in 1807.

William Brande used the same process to isolate lithium in 1821, this time using molten lithium oxide. The graph shows the melting points of the alkali metals as you go down group 1. When you click on the download symbol, you will be able to download the graph as an image file or pdf file, save its data, annotate it, and print it.

Melting points increase down group 1. If you did not know the melting point of one of the alkali metals, you could predict its approximate melting point from the graph. The melting point of caesium is just 28.5 °C. It would melt on a hot day. Francium is placed at the bottom of group 1.

  • Predict its melting point using the graph to help you.
  • Explain your answer.
  • Click to see the answer About 22 °C.
  • The graph shows that melting points decrease down the group, and the difference decreases from one element to the next.
  • Francium is below caesium, so its melting point should be a bit less than 28.5 °C.

Francium is a very rare radioactive element. Its most common isotope, 223 Fr, has a half-life of just two minutes. Only about 20 – 30 g is in the Earth’s crust at any one time. No-one has been able to collect enough of the metal to measure its actual melting point.

The alkali metals react with oxygen in the air to form metal oxides. For example, sodium reacts with oxygen to form sodium oxide: 4Na(s) + O 2 (g) → 2Na 2 O(s) You can see this happening when a piece of sodium is cut with a knife. The cut surface is silvery and shiny (as you would expect for a metal), but it rapidly becomes dull grey as sodium oxide forms.

The rate at which this happens to the alkali metals increases as you go down group 1. A piece of sodium after it has been cut in two The alkali metals react with cold water to form soluble metal hydroxides. For example, sodium reacts with water to form aqueous sodium hydroxide and hydrogen gas: 2Na(s) + 2H 2 O(l) → 2NaOH(aq) + H 2 (g) The reactions of lithium, sodium and potassium have features in common:

all three metals are less dense than water, so they floatpieces of metal get smaller as the reaction carries onbubbles are given offtheir hydroxides dissolve in the water to produce alkaline solutions – these turn universal indicator solution purple.

The equation is interesting because it contains all four state symbols:

(s) = solid(l) = liquid(g) = gas(aq) = aqueous solution

The reactions become more vigorous and rapid as you go down the group. The table describes the main differences. The video at the bottom of the page shows sodium and potassium reacting with water.

Lithium Sodium Potassium
Steady bubbling Flame not seen Rapid bubbling Metal melts and forms a silvery ball Yellow flame may be seen Sparks seen Very rapid bubbling Metal melts and forms a glowing ball Lilac flame seen Sparks seen Explosion at the end

A large mass of sodium reacting with water at night

Is Group 1 harder than Group 2?

The Parts of the Periodic Table Group 2A (or IIA ) of the periodic table are the alkaline earth metals : beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). They are harder and less reactive than the alkali metals of Group 1A.

The name comes from the fact that the oxides of these metals produced basic solutions when dissolved in water, and they remained solids at the temperatures available to the ancient alchemists. Like the Group 1A elements, the alkaline earth metals are too reactive to be found in nature in their elemental form.

The alkaline earth metals have two valence electrons in their highest-energy orbitals ( ns 2 ). They are smaller than the alkali metals of the same period, and therefore have higher ionization energies. In most cases, the alkaline earth metals are ionized to form a 2+ charge.

The alkaline earth metals have much higher melting points than the alkali metals: beryllium melts at 1287ºC, magnesium at 649ºC, calcium at 839ºC, strontium at 768ºC, barium at 727ºC, and radium at 700ºC. They are harder metals than the Group 1A elements, but are soft and lightweight compared to many of the transition metals.

Salts of the Group 2A metals are less soluble in water than those of Group 1A because of the higher charge densities on the 2+ cations; nevertheless, many Group 2A salts are at least moderately soluble. Some Group 2A salts bond strongly to water molecules, and crystallize as hydrates ; among these are Epsom salt, MgSO 4 ·7H 2 O, and gypsum, CaSO 4 ·2H 2 O.

Be, Z=4). Beryllium is a silver-white, soft metal. Its name is derived from the Greek word for the mineral beryl, beryllo, It is found in the Earth’s crust at a concentration of 2.6 ppm, making it the 47th most abundant element. The primary ores of beryllium are beryl and bertrandite, Gemstone-quality beryls include emeralds and aquamarine; the green color of these gems comes from trace amounts of chromium.

Because of its small size and high charge density, beryllium bonds through covalent bonding instead of ionic bonding. Elemental beryllium is very unreactive towards air and water, even at high temperatures. Beryllium is used to make windows for X-ray tubes (it is transparent to X-rays), and is used in alloys with other metals, such as copper and nickel, to make spark-proof tools and watch springs.

  1. Beryllium is also using in casings for nuclear weapons and in nuclear power plants because of its ability to reflect neutrons.
  2. Beryllium accumulates in bones; long-term exposure to beryllium results in inflammation in the lungs and shortness of breath (a condition called berylliosis).
  3. Mg, Z=12).
  4. Magnesium is a silver-white, relatively soft metal.

The name of the element is derived from Magnesia, a district in Thessaly in central Greece. It is found in the Earth’s crust at a concentration of 2.3%, making it the 7th most abundant element. Large amounts of magnesium are also present in the minerals in the Earth’s mantle.

  1. It is obtained from seawater, carnalite, dolomite, and magnesite,
  2. Magnesium alloyed with aluminum and traces of other metals is used in car and aircraft construction; magnesium alloys are also used in other lightweight devices, such ladders, cameras, bicycle frames, hard disk drives, etc.
  3. Magnesium is more easily oxidized than iron, and is used in sacrificial anodes to protect iron pipes and other structures that corrode easily.

Magnesium burns in air with a brilliant, and is used in fireworks and incendiary bombs. (It used to be used in disposable flashbulbs, but this use has been supplanted by other types of illumination.) Magnesium fires are very difficult to put out, since even in the absence of air, burning magnesium reacts with nitrogen to form magnesium nitride (Mg 3 N 2 ), and with water to produce magnesium hydroxide and hydrogen gas.

  • Magnesium is found in a number of familiar compounds.
  • Magnesium oxide, MgO, is used in refractory bricks that are capable of withstanding the high temperatures in fireplaces and furnaces (magnesium oxide melts at 2800 °C).
  • Magnesium sulfate heptahydrate, MgSO 4 ·7H 2 O, better known as Epsom salt, is a muscle relaxant and a mild laxative.

Magnesium hydroxide, Mg(OH) 2, also known as milk of magnesia, is a laxative and antacid. (The “milk” in “milk of magnesia” refers to the fact that since magnesium hydroxide is not very soluble in water, it tends to form a chalky, white suspension that looks like milk — but with considerably different physiological effects.) Green plants contain a molecule called, which consists of a flat ring of carbon and nitrogen atoms with a large open space in the middle, in which a magnesium ion is bound, held in place by the nitrogen atoms.

  1. The chlorophyll molecule absorbs light from the sun, and in the process of photosynthesis, the energy from the light is converted into chemical energy that the plant can use to power a multitude of processes.
  2. In organic chemistry, magnesium reacts with bromoalkanes (hydrocarbons containing carbon-bromine bonds) to form organomagnesium compounds known as Grignard reagents (after their discoverer, Victor Grignard, who won a Nobel Prize in Chemistry, 1912).

These compounds are extremely useful in forming new carbon-carbon bonds, and are often used in the synthesis of organic compounds. Grignard reagents are notoriously sensitive to water, and care must be taken to ensure that the apparatus in which the reaction is being carried out is extremely dry.

  • Ca, Z=20).
  • Calcium is a silver-colored, relatively soft metal.
  • The name of the element is derived from the Latin word for lime, calx,
  • It is found in the Earth’s crust at a concentration of 4.1%, making it the 5th most abundant element.
  • The major sources of calcium are calcite and limestone, anhydrite, gypsum, and dolomite,

Calcium salts forms the hard parts of the bodies of most living creatures, from the shells of marine organisms and the coral of coral reefs (in the form of calcium carbonate, CaCO 3 ) to the bones and teeth of land-dwelling creatures (in the form of hydroxyapatite crystals, Ca 3 (PO 4 ) 2 ] 3 · Ca(OH) 2 ).

Since calcium forms such hard minerals, it is useful in building materials, such as plaster, mortar, and cement. Mortar is made from calcium oxide, CaO, also known as lime, or quicklime. When calcium oxide is treated with water it forms calcium hydroxide, Ca(OH) 2, or slaked lime, which absorbs carbon dioxide from the air and gradually forms calcium carbonate, CaCO 3,

Lime, heated by hydrogen burning in oxygen, burns with a brilliant white light, which can be focused into a narrow beam visible over great distances. This kind of lighting was used in lighthouses, in surveying, and in theaters to produce spotlights (leaving the actor “in the limelight”).

Calcium chloride is a deliquescent (it absorbs enough water from the air that it dissolves in the solution), and is used to remove moisture from the air in damp basements. (It would take a stronger person that me to resist calling a freshly opened box of calcium chloride that wasn’t behaving properly as a “juvenile deliquescent.”) “Hard water” contains dissolved minerals having 2+ or 3+ charges, such as calcium and magnesium; these salts cause some soaps and detergents to precipitate out as “soap scum”; these minerals precipitate out over time to form “scale” in water heaters and pots.

The calcium can be removed by water softeners, which exchange the calcium ions for sodium ions, which have 1+ charges, and do not readily precipitate out. (Sr, Z=38). Strontium is a shiny, relatively soft metal. The name of the element is derived from Strontian, a town in Scotland where the mineral strontianite was discovered, from which strontium was first isolated.

  1. It is found in the Earth’s crust at a concentration of 370 ppm, making it the 16th most abundant element.
  2. It is found in the ores celestite and strontianite,
  3. Strontium salts produce brilliant red colors when heated, and are used in fireworks and flares for this reason.
  4. Radioactive strontium-90 (a beta-emitter) is produced in nuclear explosions; since it is chemically similar to calcium, it becomes incorporated into bone in people who are exposed to it.

Strontium-90 is a beta-emitter, and interferes with the production of red blood cells. (Ba, Z=56). Barium is a shiny, soft metal. The name of the element is derived from the Greek word barys, which means “heavy,” in reference to the high density of some barium minerals.

  1. It is found in the Earth’s crust at a concentration of 500 ppm, making it the 14th most abundant element.
  2. It is found in the ores barite and witherite,
  3. Barium was discovered in the 1500s in the form of the “Bologna stones” (now known to be barium sulfate, BaSO 4 ) discovered near Bologna, Italy,
  4. These stones glowed in the presence of light, and also when heated.

Barium salts give off a green color when heated, and are used in fireworks (in the form of barium nitrate, Ba(NO 3 ) 2 ). Barium sulfate, BaSO 4, is poisonous, but it is so insoluble that that it passes through the body before any absorption of barium can take place.

It is used in the diagnosis of some intestinal problems in the form of “barium enemas”: barium sulfate is opaque to X-rays, and can be used to take X-rays of the digestive tract. (Ra, Z=88). Radium is a soft, shiny, radioactive metal. The name of the element was derived from the Latin word for “ray,” radius, because of its ability to glow in the dark with a faint blue light.

It is found in the Earth’s crust at a concentration of 0.6 ppt (parts per trillion), making it the 84th most abundant element. It is found in trace amounts in uranium ores, but commercially used radium is more easily obtained from spent nuclear fuel. Radium was discovered by Pierre and Marie Curie in 1898; they extracted a milligram of radium from three tons of uranium ore.

  1. Radium is produced in the radioactive decay of uranium-235, uranium-238, thorium-232, and plutonium-241.
  2. After its discovery, and before the dangers of radiation were understood, radium was used in a lot of quack cures and patent medicines.
  3. Radium was used to make glow-in-the-dark clock faces in the early 1900’s; the alpha particles emitted by the radium struck particles of zinc sulfide, causing them to glow, but were stopped by the clock’s casing by by the glass in the clock face.

Many of the workers who painted these clock faces became ill, or died of radiation sickness.

Is Group 1 soft?

The Parts of the Periodic Table Group 1A (or IA ) of the periodic table are the alkali metals : hydrogen (H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). These are (except for hydrogen) soft, shiny, low-melting, highly reactive metals, which tarnish when exposed to air.

The name comes from the fact that when these metals or their oxides are dissolved in water, a basic (alkaline) solution results. Because the alkali metals are very reactive, they are seldom (if ever) found in their elemental form in nature, and are usually found as ionic compounds (except for hydrogen).

The alkali metals have only one valence electron in their highest-energy orbitals ( ns 1 ). In their respective periods, they are the largest elements and have the lowest ionization energies. The valence electron is easily lost, forming an ion with a 1+ charge.

The alkali metals are solids at room temperature (except for hydrogen), but have fairly low melting points: lithium melts at 181ºC, sodium at 98ºC, potassium at 63ºC, rubidium at 39ºC, and cesium at 28ºC. They are also relatively soft metals: sodium and potassium can be cut with a butter knife. Salts of the Group 1A elements tend to be extremely soluble in water.

Because the alkali metal ions are relatively large (compared to other ions from the same period), their charges densities are low, and they are easily separated from their anions and solvated by polar solvents like water. The alkali metals (again, except for hydrogen) react vigorously with water, producing the metal hydroxide, hydrogen gas, and heat.2M(s) + H 2 O(l) ® MOH(aq) + H 2 (g) (Heat plus hydrogen in an oxygen atmosphere is, of course, a very dangerous combination!) The reaction becomes more vigorous as one moves from top to bottom in Group 1A: lithium sizzles fiercely in water, a small amount of sodium reacts even more vigorously, and even a small amount of potassium metal reacts violently and usually ignites the hydrogen gas; rubidium and cesium explode.

  1. This is a result of the fact that the size of the element increases as we move down the group: as the size of the metal increases, the valence electron is farther away from the nucleus, and is thus more easily removed (i.e., the ionization energy is lower). (H, Z=1).
  2. Although hydrogen is placed at the top of Group 1A in most versions of the periodic table, it is very different from the other members of the alkali metal group.

In its elemental form, hydrogen is a colorless, odorless, extremely flammable gas at room temperature, consisting of diatomic molecules of H 2, Molecular hydrogen boils at -253 ° C (20 K), and freezes at -259 ° C (14 K). Under tremendous pressure (about 2 million atmospheres), it can be converted to a metallic form, capable of conducting electricity.

(It has been theorized that center of the planet Jupiter consists of metallic hydrogen.) In the Earth’s crust, it is found at a concentration of 1500 ppm (mostly in the form water and of organic compounds), making it the 10th most abundant element. Hydrogen is the most abundant element in the universe (75% by weight, or 88% of all of the atoms of the universe); hydrogen and helium together make up 99% of the “normal” matter of the universe.

(Of course, there’s also “dark matter” and “dark energy” to worry about, but that’s another story.) Hydrogen, helium, and trace amounts of lithium were produced at the beginning of the Universe in the Big Bang, and became concentrated into stars by the force of gravity.

  1. The fusion of hydrogen to form helium provides the power that makes stars shine: in the Sun, 600 millions tons of hydrogen undergo fusion to form helium every second, converting 5 million tons of matter into energy (Einstein’s good ol’ E = mc 2 ).
  2. The fusion of hydrogen and its isotopes (see below) also powers the hydrogen bomb, which contains lithium deuteride (LiD) and tritium; the explosion of a fission-powered bomb produces neutrons which initiate fusion of the deuterium with the tritium, releasing vast amounts of energy.

Research into achieving controlled nuclear fusion to generate electricity is being conducted, but the extremely high temperatures that are necessary to initiate the fusion reactions present a major challenge to physicists. Hydrogen typically does not form cations, but instead forms compounds through covalent bonding.

Hydrogen can form bonds to many other elements, such as nitrogen (NH 3 and its derivatives), oxygen (H 2 O) and sulfur (H 2 S), the halogens (HX), and carbon, where it is found in millions of different hydrocarbons and other organic molecules (almost all organic molecules contain at least some hydrogen atoms).

Hydrogen can also bond to metal atoms, such as lithium (LiH), calcium (CaH 2 ), etc. In these compounds, the bonding is usually pictured as a metal cation combined with a hydride anion (H – ). (On some periodic tables, in fact, hydrogen is placed at the top of Group 7A, since like the halogens, it can form a -1 charge.) Hydrogen is also found in acids, which are molecules containing easily-removed hydrogen atoms, usually connected to oxygen, nitrogen, or a halogen.

  • When dissolved in water, these substances transfer hydrogen as “H + ” (often referred to as a proton) to water, forming the hydronium ion, H 3 O +,
  • This is a greatly oversimplified explanation of acid-base chemistry.) Some commonly encountered acids include hydrochloric acid (HCl, also known a muriatic acid), sulfuric acid (H 2 SO 4 ), nitric acid (HNO 3 ), acetic acid (HC 2 H 3 O 2, the active component of vinegar), phosphoric acid (H 3 PO 4 ), hydrofluoric acid (HF), and many others.

Hydrogen was discovered by the English chemist Henry Cavendish in 1766; hydrogen had been observed before, but Cavendish was the first to recognize not only that it was an element, but that it burned to form water, which also provided conclusive proof that water was not itself an element.

The name “hydrogen” was derived by the French chemist Antoine Lavoisier from the Greek words hydro (“water”) and genes (“forming”) There are three isotopes of hydrogen. Hydrogen-1, or protium, contains one proton in its nucleus, and is by far the most common form of hydrogen (99.985% of all the world’s hydrogen).

Hydrogen-2, or deuterium, contains one proton and one neutron in its nucleus, and comprises the remaining 0.015% of the world’s naturally-occurring hydrogen. Hydrogen-3, or tritium, contains one proton and two neutrons, and is only found in trace amounts; it is produced by the interaction of cosmic rays on gases in the upper atmosphere, and in nuclear explosions, but since it has a half life of only 12.3 years, it does not accumulate in the atmosphere.

  • Heavy water is water made from two atoms of deuterium and one atom of oxygen.
  • This form of water is literally heavier than “ordinary” water, since an atom of deuterium is twice as heavy as an atom of “regular” hydrogen.
  • H 2 O has a molar mass of 18.02 g/mol; D 2 O has a molar mass of 20.03 g/mol.) Ordinary water contains about 1 molecule of D 2 O for every 7000 molecules of H 2 O.

The electrolysis of water concentrates D 2 O in the solution, since the lighter isotope evaporates from the solution slightly faster. Successive electrolysis experiments allow pure heavy water to be produced, but it takes about 100,000 gallons of water to produce 1 gallon of heavy water by this method.

Heavy water is used as a moderator in nuclear reactions: it slows down fast-moving neutrons, allowing them to be captured more easily by other nuclei. The generation of heavy water was important during the research on nuclear fission that went into the Manhattan Project during World War II. Because the deuterium in heavy water is heavier than ordinary hydrogen, the consumption of heavy water disrupts some cellular processes, especially those that rely heavily on hydrogen bonding (see below): seeds grown in heavy water do not germinate, and rats die after a week of drinking nothing but heavy water, when their body water reaches 50% deuteration.

(For a typical person, a fatal dose would require drinking nothing but heavy water for 10 to 14 days, so it’s pretty doubtful that heavy water poisoning will be featured on CSI anytime soon.) Most hydrogen is prepared industrially be reacting coal or hydrocarbons with steam at high temperatures to produce carbon monoxide and hydrogen gas (a mixture of carbon monoxide and hydrogen is called synthesis gas, and can be used in manufacturing methanol).

On smaller scales it can be produced by the reaction of active metals (such as zinc, calcium, etc.) with hydrochloric acid, or by the electrolysis of water. Hydrogen gas is combined with nitrogen in the Haber process to synthesize ammonia (NH 3 ), which is widely used in fertilizers. It is also used in the manufacture of hydrogenated vegetable oils; in this reaction, hydrogen atoms add to the carbon-carbon double bonds in the vegetable oils (double-bonded carbons bond to fewer hydrogen atoms than single-bonded carbons — i.e., they are unsaturated with respect to hydrogen), converting them into saturated fats, which are generally solids at room temperature.

Another use for hydrogen is in rocket fuels: the Saturn V rockets that launched the Apollo lunar missions used 209,000 gallons of kerosene and 334,500 gallons of liquid oxygen in its first stage (S-IC), 260,000 gallons of liquid hydrogen and 83,000 gallons of liquid oxygen in its second stage (S-II), and 69,500 gallons of liquid hydrogen and 20,150 gallons of liquid oxygen in its third (S-IVB) stage; the Space Shuttle main engines use 385,000 gallons of liquid hydrogen and 143,000 gallons of liquid oxygen.

Hydrogen is lighter than air, and was used in balloons and dirigibles (also known as airships or zeppelins). Dirigibles were used in city-to-city air travel in the early 1900s, and in trans-Atlantic crossings in the 1920s and 1930s. (During World War I, German zeppelins were used in bombing runs over England, since they could fly higher than the British planes.) On May 6, 1937, the German dirigible Hindenburg caught fire as it came in for a landing at Lakehurst Naval Air Station in New Jersey; 35 people out of the 97 aboard and one person on the ground were killed.

The exact cause of the fire is still the subject of speculation, but the disaster signaled the beginning of the end for airship travel. Modern “blimps” use helium to provide lift, which avoids the problem of hydrogen’s flammability. Molecules which contain hydrogen bonded to nitrogen, oxygen, or fluorine can attract one another through the formation of hydrogen bonds,

  1. Hydrogen bonds are a particularly strong form of dipole-dipole forces, which arise because of the unequal sharing of electrons in some covalent bonds.
  2. If one atom in a covalent bond is more electronegative than the other, it “pulls” harder on the electrons that the two atoms share, giving the more electronegative atom a partial negative charge, and the less electronegative atom a partial positive charge.

The partially negative atom on one molecule attracts the partially positive atom on a neighboring molecule, causing the two molecules to be more attracted to each other than two nonpolar molecules (which have no electronegativity differences between their bonded atoms) would be.

  1. Molecules that interact by these dipole-dipole forces tend to have higher boiling points than nonpolar molecules, because higher temperatures are necessary to overcome the attractive forces between the molecules and separate the molecules into the gas phase.
  2. In the case of O—H, N—H, and F—H bonds, the electronegativity differences are particularly large because fluorine, oxygen, and nitrogen are the most strongly electronegative elements.

The attractive forces between molecules containing these bonds are particularly strong, and are given the name hydrogen bonds, Hydrogen bonds are not as strong as covalent bonds, but they greatly influence the physical properties of many substances. In particular, hydrogen bonds are responsible for the fact that water is a liquid at temperatures at which molecules of similar molecular mass are gases.

(For instance, hydrogen sulfide, H 2 S, which weighs 34.08 g/mol, boils at -60.28 ° C, while water, weighing in at a measly 18.02 g/mol, boils at 100 ° C.) Ice floats on liquid water because the hydrogen bonds hold the molecules into a more open, hexagonal array, causing the solid form to be less dense than the liquid form.

In living systems, hydrogen bonding plays a crucial role in many biochemical process, from the coiling of proteins into complex three-dimensional forms to the structure of the DNA double helix, in which the two strands of DNA are held together by the hydrogen bonding between their nucleic acids components.

  • Hydrogen is also important in a form of spectroscopy called Nuclear Magnetic Resonance (NMR).
  • In this technique, a sample is placed in a powerful magnetic field (usually produced by a superconducting magnet — see the section on ), which causes the hydrogen atoms in the sample to resonate between two different magnetic energy levels; pulsing the sample with a burst of radiofrequency radiation (typically between 200 to 500 MHz) causes the hydrogen atoms to absorb some of this radiation, producing a readout called an “NMR spectrum” which can be used to deduce a great deal of structural information about organic molecules.

Since almost all organic molecules contain hydrogen atoms, this technique is widely used by organic chemists to probe molecular structure; it can also be used to determine a great deal of information about extremely complex molecules such as proteins and DNA.

The technique is nondestructive, and only requires small amounts of sample. NMR spectroscopy can also be performed with the carbon-13 isotope, and several other isotopes of other elements. This technology is also used in an important medical imaging technique called Magnetic Resonance Imaging (MRI); the water molecules in different environments in the body respond to very slightly different magnetic field strengths, allowing images of tissues and organs to be obtained.

This technique can be used in diagnosing cancers and creating images of tumors and other diseased tissues. MRI is also used to study how the brain works by looking at what areas of the brain “light up” under different stimuli. (The term “nuclear” is avoided in the medical application because of its unpleasant associations, even though the only radiation involved is similar to that of an FM radio transmitter).

  • Li, Z=3).
  • Lithium is a soft, silvery metal, with a very low density, which reacts vigorously with water, and quickly tarnishes in air.
  • The name of the element is derived from the Greek word for stone, lithos,
  • It is found in the Earth’s crust at a concentration of 20 ppm, making it the 31st most abundant element.

It is found in the ores spodumene, petalite, lepidolite and amblygonite, Lithium also presents some exceptions to the “typical” Group 1A behaviors. The lithium ion has a very high charge density because of its small size; thus, many lithium salts have significant covalent-bonding character, instead of being purely ionic.

These salts dissociate less easily in water than the salts of sodium and potassium, and are therefore less soluble in water. In addition, lithium can form bonds to carbon which have high covalent character (the organolithium compounds ). Lithium was one of the three elements produced in the Big Bang, although it was produced only in trace amounts.

Aluminum and magnesium alloys of lithium are strong and lightweight; aluminum-lithium alloys are used in aircraft construction, trains, and bicycles. Lithium-based batteries have very long lifetimes (particular important in implantable devices such as pacemakers and defibrillators), and are very lightweight; they are frequently used in portable electronic devices and computers.

Lithium salts (such as lithium carbonate, Li 2 CO 3 ) are used in the treatment of bipolar disorder and some types of depression, and are also used to augment the actions of other antidepressants. Lithium deuteride (LiD, see entry on Hydrogen above) is used in hydrogen bombs; neutrons produced by a fission-powered explosive are absorbed by the lithium atoms, transforming them into tritium; the fusion of tritium and deuterium to form helium releases tremendous amounts of energy.

Lithium hydroxide (LiOH) is used in confined spaces to remove carbon dioxide from the air (the carbon dioxide is captured in the form of lithium carbonate); this is particularly important in submarines and spacecraft. (Na, Z=11). Sodium is a soft, silvery metal that reacts very vigorously with water, and tarnishes easily in air.

  • It is the fourth most abundant element in the Earth’s crust, which consists of 2.6% sodium by weight; seawater is about 1.5% sodium.
  • The name is derived from the English word soda, a term found in many compounds of sodium, such as washing soda (sodium carbonate or soda ash), sodium bicarbonate (baking soda), and sodium hydroxide (caustic soda).

The symbol “Na” is derived from the Latin name for the element, natrium, It is found in the minerals halite and trona, and can be extracted from seawater. Of the salt that is obtained from these sources, 60% is converted to sodium hydroxide, chlorine, or sodium carbonate; another 20% is used in the food industry as a preservative and flavoring agent, and another 20% is used for other applications, such as de-icing roads.

  1. Metallic sodium is usually stored in mineral oil or some other hydrocarbon, because it will react with the moisture in the air to form sodium hydroxide.
  2. A common laboratory demonstration illustrates the reactivity of sodium.
  3. A small piece of sodium placed in a dish of water skates around on the surface of the water, hissing violently, and slowly disappears.

The sodium reacts with water in a single-displacement reaction, producing sodium hydroxide and hydrogen gas: 2Na(s) + H 2 O(l) ® NaOH(aq) + H 2 (g) The sodium hydroxide is soluble in water, and dissolves. This demonstration can become very dangerous if too large a piece of sodium is used, however, since enough heat can be generated to ignite the hydrogen gas.

  • Sodium also reacts vigorously with chlorine gas, producing sodium chloride: 2Na(s) + Cl 2 (g) ® 2NaCl(s) This reaction releases a great deal of heat energy, and is usually done in a beaker lined with sand to prevent the heat from cracking the glass.
  • See for a demonstration.) Energetically excited sodium atoms glow with a yellow light (the strongest emissions are the “sodium D-lines” at 589.0 and 589.5 nanometers), and are prominent in the light from many stars (including the Sun).

Sodium is also used in sodium-vapor street lamps. In the body, sodium ions regulate osmotic pressure and blood pressure, and sodium and potassium ions together play a major role in the transmission of nerve impulses. One of the most important compounds of sodium is sodium chloride, NaCl, also known as table salt.

  1. Commercially prepared sodium chloride is either mined in the form of halite, from deposits formed by ancient, dried-out sea beds, or by the evaporation of water from sea water.
  2. Sodium chloride is subjected to electrolysis in an apparatus called a Downs cell, which produces sodium metal and chlorine gas; the construction of the cell is designed to keep the sodium and chlorine separate from each other as they are produced.

Sodium carbonate, Na 2 CO 3, also known as soda or soda ash, has been used for centuries in washing clothes (it helps to remove highly charged metal cations, such as calcium and magnesium, from hard water) and in the manufacture of glass, paper, and detergents.

Sodium hydroxide, NaOH, also known as caustic soda or lye, is a strong base; it is used in drain cleaners, and in the manufacture of detergents (sodium hydroxide breaks down triglycerides — fats and oils such as lard, shortening, olive oil, vegetable oils, etc. — to produce carboxylate salts that form effective soaps).

Sodium bicarbonate, NaHCO 3, also known as sodium hydrogen carbonate, is the main ingredient in baking soda, and is used as a leavening agent in the making of bread and other baked goods. (K, Z=19). Potassium is a soft, silvery metal that reacts extremely vigorously with water, and tarnishes rapidly in air.

  1. Its name is derived from the English word “potash,” for potassium carbonate, a compound found in high concentrations in wood ashes.
  2. The symbol “K” is derived from the Latin name for the element, kalium,
  3. Potassium is the eighth most abundant element in the Earth’s crust (2.1%).
  4. The main ores in which potassium is found are sylvite, carnallite, and alunite,

Potassium is essential for plant growth, and is heavily used in fertilizers. In the body, potassium plays a vital role in the contraction of muscle tissue; the movement of sodium and potassium ions in nerve cells plays a major role in the transmission of nerve impulses.

  • When heated, potassium salts glow with a purple color, and are used in fireworks.
  • Like sodium, metallic potassium is usually stored under mineral oil or some other hydrocarbon; it can also react with oxygen in dry air to produce potassium superoxide, KO 2 (see below).
  • Potassium undergoes a a reaction with water similar to that of sodium; the products of the reaction are potassium hydroxide and hydrogen gas.

This reaction releases a great deal of heat energy, often igniting the hydrogen gas that is produced. Potassium-40, which accounts for 0.0117% of the world’s potassium, is radioactive, with a half-life of 1.25 billion years. It undergoes electron capture to produce argon-40; a comparison of the ratio of potassium-40 to argon-40 in rocks can be used to determine the age of the rock (potassium-argon dating).

  • Trace amounts of potassium-40 are found in all sources of potassium; in a typical human, about 170,000 atoms of potassium-40 decay every second.
  • The energy released by the decay of potassium-40 is partially responsible for the interior heat of the Earth, along with the decays of thorium and uranium.
  • There are a number of widely-used compounds of potassium.

Potassium chloride, KCl, is used in salt substitutes (mixed with sodium chloride to improve its flavor), and in fertilizers; massive amounts of potassium chloride are used in lethal injections to cause rapid death by cardiac arrest. Potassium carbonate, K 2 CO 3, also known as potash, is used in the manufacture of glass.

  • Potassium hydroxide, KOH, also known as caustic potash, is used in making soaps and detergents.
  • Potassium nitrate, KNO 3, also known as saltpeter, is a powerful oxidizer, and is one of the ingredients of gunpowder.
  • Potassium chlorate, KClO 3, is a very powerful oxidizer, and is used in match heads and fireworks.

Potassium superoxide, KO 2, reacts with carbon dioxide to produce potassium carbonate and oxygen gas; it is used in rebreathers and respiration equipment to generate oxygen, and is also used in mines, submarines, and spacecraft. (Rb, Z=37). Rubidium is a soft, white metal; it is similar to sodium and potassium in its reaction with water, but the reaction is even more violently exothermic.

  • Its name is derived from the Latin word for deep red (ruby), rubidius,
  • It is found in the Earth’s crust at a concentration of 90 ppm, making it the 22nd most abundant element.
  • It is not found in any unique minerals, but is present in trace amounts in lepidolite, pollucite, carnallite, zinnwaldite, and leucite.

Rubidium melts at 39ºC (102ºF), so in Texas (where I am writing this) it may be a liquid instead of a solid if the air conditioning isn’t working that day. Metallic rubidium spontaneously combusts in air. In flame tests, rubidium salts produce a reddish-violet color, and are sometimes used in fireworks.

Rubidium is used in the manufacture of vacuum tubes and cathode ray tubes (CRTs), and is used in some atomic clocks. In 1995, a vapor consisting of 2000 rubidium-87 atoms was cooled to 170 nanokelvins (170 ´ 10 -9 degrees above absolute zero), producing the first Bose-Einstein condensate, a bizarre state of matter in which all of the atoms occupy the same quantum state, effectively acting as a single superatom (Nobel Prize in Physics, 2001).

(Cs, Z=55). Cesium (also spelled as “caesium”) is silvery-gold colored metal, which melts at 28ºC (82ºF); a sample of cesium will melt in your hand (not that I’d recommend doing this!). Cesium undergoes the same reaction in water as lithium, sodium, and potassium, but even more violently; because cesium is a very large atom, the outermost electron is lost very easily, and the process is extremely exothermic.

The name is derived from the Latin word caesius, which means “sky blue,” because salts of cesium produce a blue color when heated. Cesium is found in the Earth’s crust at a concentration of 3 ppm, making it the 46th most abundant element. The main ore of cesium is pollucite ; the refining of pure cesium is made even more difficult by the presence of trace amounts of rubidium in the ore, which is chemically very similar to cesium and thus difficult to separate.

Because cesium is so reactive, it is used as a “getter” to remove all traces of other gases from vacuum chambers, cathode ray tubes, and vacuum tubes. Some cesium salts give off light when exposed to X-rays and gamma rays; they are also used in photoelectric cells.

  • Cesium is used in atomic clocks.
  • In the SI system, a second is defined as 9,192,631,770 cycles of the radiation corresponding to the energy difference between the ground state and one of the excited states of the cesium-133 atom.
  • Radioactive cesium-137 is produced in the testing of nuclear weapons, and in nuclear power plants; the explosion at the Chernobyl power plant in 1986 released large amounts of cesium-137, which contaminated a great deal of Western Europe.

Cesium-137 has a half-life of 30 years, and undergoes beta-decay to produce barium-137m, a metastable isotope of barium with a half-life of 2.6 minutes, which emits gamma rays to produce stable ground-state barium-137. Since cesium ions are so heavy, research on the use of cesium in ion propulsion drives aboard spacecraft and satellites is being conducted.

Fr, Z=87). Francium is an extremely rare, radioactive metal. Its is named for France, the country in which it was first isolated. It is found in the Earth’s crust only in trace amounts, and is one of the least abundant elements on the Earth. Traces of it are found in uranium ores, where it is produced in the decay series of uranium-235; there is probably only about 20 to 30 grams of naturally-occurring francium in the entire Earth.

All of the isotopes of francium are radioactive, and most have half-lives of less than five minutes; the longest-lived isotope (francium-223) has a half-life of 21.8 minutes. The possible existence of francium was predicted by Mendeleev from a gap in his periodic table, but the element wasn’t discovered until 1939, by Marguerite Perey, an assistant to Marie Curie at the Radium Institute in Paris.

What is the salary of Group 2 exam in Tamilnadu?

After joining, the Group 2 employees will be received the salary as per the 7th pay commission. The TNPSC Group 2 in-hand salary includes the basic pay+ grade pay+ dearness allowance+ some additional allowances. The TNPSC Group 2 salary range is INR 37200 to INR 117600 per month.

What is the fees of Group 1 exam in Tamilnadu?

TNPSC Group 1 Exam Fee – The TNPSC Group 1 Exam Fee consists of three different stages. They are the Registration Fee, Preliminary Examination Fee and Main Written Examination Fee. Registration Fee The One-Time Registration(OTR) Fee for TNPSC Exam is Rs.150/-.

  • Applicants who have already registered in the OTR system and are within the validity period of 5 years are exempted.
  • Candidates who have registered can pay the examination fee alone.
  • Preliminary Examination Fee The TNPSC Group 1 Preliminary Examination Fee is Rs 100/-.
  • The Preliminary Examination fee should be paid at the time of submitting the online application for this recruitment.

Main Written Examination Fee The TNPSC Group 1 Mains Examination Fee is Rs.200/-. The candidates who have cleared the preliminary examination have to pay the main written examination fee on receipt of intimation from TNPSC.

What is the salary of Group 2 exam jobs in Tamilnadu?

TNPSC Group 2 Salary Structure: Post-Wise Salary

Service name Post name TNPSC Group 2 Salary
Tamil Nadu Secretariat Service Assistant Section Officer in the Finance Department in the Secretariat Rs.36,400-1,15,700 (Level-16)
Tamil Nadu secretariat service Assistant Section Officer in the Finance Department in the Secretariat

What is the salary of IAS in Tamil Nadu?

IAS Salary per Month – As per the latest 7th Pay commission, the IAS Officer Salary per Month in the beginning and at the entry level is ₹56100, which leads to ₹56100 – 132000 per month. After years of service and each promotion, the IAS salary in India per month increases.

What is the salary of BDO in Tamil Nadu?

Block Development Officer(BDO) Salary Structure
Pay Band Pay Band 2
Level Pay Scale 6
Basic Pay Rs 18,500 – Rs 45,500
Grade Pay Rs 4700

Is a2 2 a good degree?

Is a 2.2 degree good? – In short, yes. You can still get a good graduate job with a 2.2 degree. The direction that a lot of employers are moving in is away from viewing a first or 2.1 as the be all and end all.

What is the age limit for Group 2 in Tamilnadu?

By Shiwani Kumari | Updated on: Mar 29, 2023 TNPSC Group 2 age limit is prescribed by the Tamil Nadu Public Service Commission. Candidates should be well aware of all eligibility details such as TNPSC Group 4 age limit, Educational Qualification, Number of Attempts, etc. Show Full Exam Details

Which online class is best for TNPSC Group 1?

If you are of them willing to become one of those officers listed down here, then you must have online coaching where you can frame your base to crack the exam easily. Therefore, KingMakers IAS Academy is the best tnpsc group 1 online coaching that can guide you! TNPSC Group 1 is a recruitment exam every year conducted by the Tamil Nadu Public Service Commission ( TNPSC ).

Which institute is best for TNPSC Group 1 in Chennai?

Best TNPSC Coaching Centre in Chennai, such as Eva Stalin IAS Academy, Dream Institute, Kamaraj IAS Academy, Kalam IAS Academy, Ram IAS Academy, assist students in preparing for the TNPSC exam.

Arjun Patel