Transition metals - Lecture notes 1 PDF

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SCANDIUM  Weakly basic Occ./Uses  mineral ore  Residues in Uranium processing  A component in highly-intensity lights.  Scandium iodide is added to mercury vapor lamps to produce lights similar to sunlight for film and tv.  Scandium and aluminum combined make a light but strong alloy used for sports equipment and fighter jets.  Scandium-46 is a radioactive isotope which can be used to detect leaks in underground pipes. TITANIUM Occ./Uses:  Titanium is ilmenite (FeTiO3)  Resistant to corrosion at ambient temp.  Lightweight and strong, making it valuable as a component in alloys, e.g. in aircraft construction.  Superconducting magnets.  Titanium dioxide is a key component of sunscreens, stopping UV light from the sun reaching the skin.  Many international space station parts are titanium—it’s strong, light, and copes in extreme temp.  Ti metal is used to make artificial joints as it is biocompatible and resists corrosion. VANADIUM Occ./Uses:  Alloys are used for spring and high speed cutting-tool steels.  Catalyst – V2O5  V is added to steel to increase its hardness.  Vanadium (V) oxide is used to give ceramics a golden color. Added to glass giving a blue or green tint.  Sea cucumbers have Yellow Blood due to the presence of vanabins (a Vanadium –binding protein). CHROMIUM Come from the Greek word for color, chrome. It is Weakly acidic Occ./Uses:  Chromium is Chromite (FeCr2O4)  Corrosion Resistant – Manufacturing stainless steel  Chromium plating – tools, cars, jewelry, silverware  Wood preservation  Chromium impurities in structure are responsible for the red color of rubies.  Plating with a layer of chromium is used to decorate metals and protect them from corrosion.  The yellow color of school busses is due to chromium-containing pigment, chrome yellow. MANGANESE  Strongly Acidic. Occ./Uses:  Essential to iron and steel production  Low cost stainless steel formulation  Dry cell batteries.  KMnO4 = strongly oxidizing power  Small amounts of MnSO4 are added to fertilizers.  Manganese steel contains approx. 13% manganese. It is strong and used in railways, safes, and prison bars.  It is essential for organisms. It is needed for string bones, and many enzymes also contain it.  Drinks cans are made with an alloy of aluminum and manganese, which helps prevent corrosion. IRON  The most important of all metals. Occ./Uses:  The 4th most abundant element in the Earth’s Crust.  It is mixed with other metals and with carbon to create a variety of steels with different properties.  Very active metal.  Combines with oxygen in moist air to form iron oxide (rust).  Reacts with very hot water and steam to produce hydrogen gas.  Reacts with many other elements (activity series) and dissolves in most acids.  Blood’s red color is from the iron of hemoglobin.  The surface of mars is red due to iron oxide (rust).  Movement of iron in the outer core generates a magnetic field.  Plays a central role in most all living cells.  Involves in electron-transport chain COBALT Occ./Uses:  Silvery-blue and brittle.  Occurs as a number of sulfide and arsenide ores.  Cobalt blue is a blue colored pigment used in paints and as a coloring agent in Chinese porcelain.  Alloys of cobalt stay strong at high temp. and resist corrosion. They are used in jet engines.  Radioactive cobalt-60 is used to sterilized medical equipment, and also used for food irradiation NICKEL (weakly basic) Occ./Uses:  Occurs as sulfide and arsenide minerals  An important catalyst for the hydrogenation of unsaturated organic compounds  Nichrome is a nickel-chromium alloy that is used as heating elements in toasters and electric ovens.  Nickel is one of the only four elements that’s magnetic at 20 0C. The others are Iron, cobalt, and Gadolinium

 The coins used in many countries contain nickel, alloyed with other metal such as copper.  The Iron Triad: 3 elements in period 4----iron, cobalt, and nickel have such similar properties. They are known as “The Iron Triad”.  Industrial magnets are made from an alloy of nickel, cobalt and aluminum.  Nickel is used in batteries along with Cadmium. COPPER Occ./Uses:  the least reactive of the first row metals.  CuSO4 can be use as fungicide.  Analytical application – biuret test and Fehling’s solution ZINC Occ./Uses:  Used to galvanize (coat) other metals to stop rusting. Galvanized steel is used in cars and streetlights.  Zinc oxide is used in sunscreen as it scatters UV light. CHROMIUM Acidic solution Basic Solution

+2 Cr2+(aq) Blue Cr(OH)2(s) Light Blue

+3 +6 Cr3+(aq) Violet Cr2O72-(aq) Orange Cr(OH)3(s) Pale green CrO42Yellow Cr(OH)4 (aq) Deep green A reaction of Chromium metal with 6 M H2SO4 in the absence of air gives bubbles of H2 gas and a solution containing the blue Cr2+ ion. A reaction of Chromium metal with 6 M HCL in the presence of air yields a green solution containing Cr 3+ species. Cr(s) + 2H+(aq) Cr2+(aq) + H2(g) + 4 Cr + O2(g) + 4H (aq) 4 Cr3+(aq) + 2H2O(l) In acid: Cr(OH)3(s) + 3H3O+(aq) Cr3+(aq) + 6H2O(l) Cr(OH)4-(aq) In excess base: Cr(OH)3(s) + OH (aq) 2+ (aq)

Remember Acid Strength increases with increasing oxidation number of the atom to which an OH group is attached. Chromium (VI) compounds must be handle with care because they are highly toxic and can cause cancer. IRON, Fe+2/+3 + Fe(s) +2H (aq) Fe2+(aq) + H2(g) Fe2+(aq) Fe3+(aq) + eFe2+(aq) + O2(g) + 4H+(g) 4Fe3+(aq) + 2H2O(l) Fe(s) + NO3-(aq) + 4H+ (aq) Fe3+(aq) + NO(g) + 2H2O(l) COPPER, CU+1/+2 2Cu(s) + O2(g) + CO2(g) + H2O(g) Cu2(OH)2CO3(s) Cu2(OH)2CO3(s) + H2SO4(aq)Cu2(OH)2SO4(s) + CO2(g) + H2O(l) 3Cu(s) + 2NO3-(aq) + 8H+ (aq) 3Cu2+(aq) + 2NO(g) + 4H2O(l) Cu+(aq) + eCu(s) Cu+(aq) Cu2+(aq) + e2 Cu+(aq) Cu(s) + Cu2+(aq) 2 Cu+(aq) Cu(s) + Cu2+(aq) 2+ Cu(s) + Cu (aq) + 2Cl (aq) 2CuCl(s) Reaction of Cu2+(aq) with aqueous Ammonia When an aqueous solution of CuSO 4 is treated with aqueous ammonia, a blue precipitate of Cu(OH) 2 forms: Cu2+(aq) + 2OH-(aq) Cu(OH)2(s) On the addition of excess Ammonia, Cu(OH)2 dissolves, yielding the deep blue Cu(NH3)42+ ion. Cu(OH)2(s) +NH3(aq) Cu(NH3)42+(aq) + 2OH-(aq) YTTRIUM Occ./Uses:  Yttrium oxide is added to the glass in camera lenses to make them heat and shock resistant.  Yttrium aluminum garnet is used to simulate some gemstones, and is also found in some lasers.  Blue LEDs can be given a coating of cerium-doped yttrium aluminum garnet to make them appear white. ZIRCONIUM Occ./Uses:  the next most abundant d-block metal in the Earth’s crust after Fe, Ti, and Mn.  Zirconium oxide is used in ceramic knives which stay sharper for longer compared to steel knives. NIOBIUM Occ./Uses:  Niobium and some its alloys are hypoallergenic and is used in prosthetics, pacemakers, and jewelry.  Niobium oxide increases the refractive index of glass, allowing corrective glasses to have thinner lenses. MOLYBDENUM Occ./Uses:  it is added to steel to make it stronger, resistant to corrosion, and heat resistant.  Molybdenum disulfide is used as a dry lubricant in both motorcycle and aircraft engines.  Molybdenum-containing enzymes process the sulfites in wine, cheese, pickles, and other foods. TECHNETIUM Occ./Uses:  The first element in the periodic table to be made artificially by the Italian scientists.  It is the lightest element whose isotopes are all radioactive. It is produced as a fission waste product. RUTHENIUM Occ./Uses:

 Is used to harden alloys of platinum and palladium used in electronics and switches.  Fountain pen nibs are tipped with hard-wearing ruthenium, osmium and rhenium alloys.  Ruthenium trioxide is used to expose latent fingerprints as the fats in the print turn it black. RHODIUM Occ./Uses:  It is used in catalytic converters in cars, breaking down nitrogen oxides in exhaust gases.  White gold jewelry is often electroplated with rhodium to improve its appearance.  It is the rarest non-radioactive metal, and is also one of the least radioactive elements. PALLADIUM Occ./Uses:  Its main use is as a catalyst, in car catalytic converters and in some organic chemistry reactions.  It can absorb 900 times its own volume in H2 gas and maybe used for hydrogen fuel storage. SILVER Occ./Uses:  Threads of silver are woven into gloves so they can be used to operate touch-screen devices.  Light-sensitive silver halides are used in film photography.  Silver nanoparticles have antibacterial properties and are woven into clothes to prevent odors. CADMIUM Occ./Uses:  its main use is in rechargeable nickel-cadmium batteries, but these are being phased out.  Cadmium pigments give paints yellow, orange and red hues.  Its high toxicity has led to pushes in many countries to reduce its supply and use. LANTHANUM Occ./Uses:  Lanthanum oxide is used in camera lenses to reduce dispersion and improve clarity of images.  It is found alloyed with other metals in the anodes of hybrid car batteries.  Lanthanum compounds are added to pools to remove phosphates and stop algae growth. HAFNIUM Occ./Uses:  It is a neutron absorber and is used in nuclear reactor control rods in nuclear submarines.  Hafnium oxide is used as electrical insulators in microchips, helping make them smaller and faster.  Because of its high melting points, it is used in plasma cutting tips and welding torches. TANTALUM Occ./Uses:  Its Min use is for electronic components (e.g. capacitors) in phones, laptops, and cameras.  It is used in dental and surgical instruments and implants as it doesn’t trigger immune response.  Tantalum is found in strong alloys used for turbine blades and noses of supersonic aircraft. TUNGSTEN Occ./Uses:  Tungsten carbide is harder than steel and is used in drill bits, armor-piercing bullets, and mining tools.  It was used in the filaments of incandescent light bulbs, now phased out in most countries.  As its density is very similar to that of gold, tungsten has been used to make counterfeit gold bars. RHENIUM Occ./Uses:  Its main use is in high temperature ‘super alloys’, which are used in jet engines parts.  A rhenium platinum alloy is used as a catalyst in the process to make lead-free high-octane petrol  It is added to tungsten and molybdenum alloys in oven filaments and X-ray machines. OSMIUM Occ./Uses:  Hard alloys of Osmium and its neighbor, iridium, are often used in tips of fountain pens.  Osmium tetroxide is used as a straining agent in some types of microscopy to make clearer images.  It is the densest element in the periodic table, with density about twice that of lead’s. IRIDIUM Occ./Uses:  The most corrosion-resistant metal, iridium is alloyed with osmium and used in pen tips and compass pivot points  Because of its high melting point and low reactivity, it is used in spark plugs, particularly in aviation.  The impact that wiped out dinosaurs 66 million years ago left a layer of iridium-rich clay in Earth’s Crust. PLATINUM Occ./Uses:  Because of its resistant to corrosion, it is used in jewelry and as an electrode material.  It is one of the metals used in catalytic converters in cars, and as a catalyst for the other reactions. MERCURY Occ./Uses:  the only metal which is liquid at room temp. it melts at -39 0C.  Mercury and many of its compounds are toxic. Mixed with other metals it can be safely used in fillings.  The phrase “mad as a hatter” is from the illness caused by mercury(II) nitrate (which was used in making hat felt). ACTINIUM Occ./Uses:  It is a silvery-white metal that glows blue in the dark as its radioactivity excites the air around it.  It is scarce and has few uses. Actinium-225 has been investigated for cancer treatment.  Actinium-227 is about 150 times as radioactive as radium, and is used as a neutron source. RUTHERFORDIUM Occ./Uses:  Rutherfordium’s longest isotope has a half-life of 1.3 hours. It has no use outside research. DUBNIUM Occ./Uses:  Named after Dubna, Rusia which is where the element was first made and detected.  Longest lived isotope has a half-life of around a day. no use outside research. SEABORGIUM Occ./Uses:  The first element named after a living person: Glenn Seaborg, the co-discoverer of 10 elements.  Longest lived isotope has a half-life of 14 minutes.

BOHRIUM Occ./Uses:  Created by German scientists and named after Danish physicist Niels Bohr.  The first element made by colliding two nuclei in a low excitation energy cold fusion reaction was Bohrium.  Longest lived isotope has a half-life of about a minute. HASSIUM Occ./Uses:  Created by German scientists and named after German State of Hesse  It is predicted that Hassium’s density is 41 g/cm, nearly twice the observed density of an element.  Longest loved isotope has a half-life of 16 seconds DARMSTADIUM Occ./Uses:  Named after Darmstadt, Germany, which is where the element was first produced  Policium was suggested as a joke for this element’s name. 110 is the emergency number in Germany.  Longest lived isotope has a half-life of about 13 seconds. ROENTGENIUM Occ./Uses:  Named after the german physicist Wilhem Rontgen, who discovered X-rays.  Predicted to be silver in color. Longest lived isotope has a half-life of about 100 seconds. COPERNICIUM Occ./Uses:  Named after astronomer Nicolaus Copernicus, conformed on his 537th Bday.  Due to relativistic effects, it is thought to be a volatile liquid that acts like a noble gas.  Longest lived isotope has a half-life of about 28 seconds. USES OF TRANSITION ELEMENTS  Mercury has the lowest melting point of any metal (-39 0C), is used in thermometers and barometers.  Amalgam (familiar of “silver filling”) is a mixture of silver, copper, tin, and mercury, that dentists have been using to fill cavities in decayed teeth.  Ruthenium, Rhodium, Palladium, Osmium, Iridium, and Platinum are sometimes called the Platinum Group because they have similar properties. They don’t combine as easily with other elements. As a result, they can be used as catalyst.  Iron – catalyst production of Ammonia (Haber Process)                        

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INNER TRANSITION ELEMENTS The first series, from cerium to lutetium, is called the LANTHANIDES. The second series from Thorium to Lawrencium, is called the ACTINIDES ACTINIDES: GENERAL BACKGROUND Rare earth Metals Highly dense matals High MP than the d-block No stable Isotopes and are radioactive 1st actinides discovered: Uranium and Thorium Mostly man-made products of the 20th Century (bombardment techniques) Only Actinium, Thorium, Protactinium & Uranium occur naturally. Actinium & Protactinium occur in trace amounts. Neptunium and Plutonium occur in Uranium minerals in Minute amounts. LANTHANIDES: GENERAL BACKGROUND The rare earth elements of the modern periodic table. They are called the “rare earth metals” because their occurrences are very small They are available in monazite sand as lanthanide orthophosphates. Most common minerals: Bastnaesite (A La, Ln fluorocarbonate MIIICO3F) – a vast deposit in Sierra Nevada, USA Silvery white, but tarnish in air Rather soft (later Metals are harder) High MP and BP Very reactive Burn easily in air but slowly in cold. Burn @ T > 150 0C. React readily with C, N2, Si, P, halogens & other non-metals. 3ppm of the Earth’s crust. URANIUM  Widely distributed – found scattered in faults of old igneous rocks  Used in nuclear fuel, and on a smaller scale for coloring glass/ceramics PROTACTINIUM  Discovered as the last from the naturally occurring actinides  The rarest and most expensive of the naturally occurring actinides elements. APPLICATIONS OF TRANSURANIUM ELEMENTS  Nuclear fuel  Nuclear weapons  Neutron Sources  depleted uranium armor and projectiles heart pacemakers heat sources, space energy sources actinium-225 is used in alpha-particle generators for tumor radiotherapy  smoke detectors  Lantern mantle  catalyst

LANTHANIDES Besides +3 oxidation state they show +2 & +4 oxidation States only in a few cases. They have less tendency towards complex formation Lanthanide compoounds are less basic.

SIMILARITIES Both show mainly an oxidation state of +3 Both are electropositive and very reactive Both exhibit magnetic and spectral properties Most ions are colored Actinides exhibit Actinide contraction like lanthanide contraction shown by lanthanodes.

ACTINIDES Besides +3 oxidation state, they show higher oxidation states of +4, +5, +6, +7 also. They have greater tendency towards complex formation Actinides compounds are more basic.

ACTINIDE CONTRACTION Actinide contraction is analogous to the lanthanide contraction. REASON: with increase of atomic number, the nuclear charge increases and attracts more effectively the outer electron shell  Ionic radii of the same oxidation states systematically decrease. EFFECT: smaller radius causes cationic charge density  more rapid hydrolysis and complex formation. USE: An(III) and Ln(III) are separated from each other mainly on the basis of difference in ionic radius. ELECTRONIC CONFIGURATION  electronic configurations of actinides are not always easy to confirm.  Filling up the 5f orbitals from Th to Lr  5f close in energy to 6d and 7s in particular in Z=90-94  electronic configurations of actinides consist from the closed redon shell, followed by two 7s and 5-f electrons, 6-d electrons is present sonly in light An (Z...