India 2025 — INChO2025-Question.pdf

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Problema 1

Problem 1

23 marks The golden alloy

Two or more metals can form an alloy if they have I. similar atomic radii, differing by less than 15% II. same crystal structure, and III. similar chemical properties or similar number of valence electrons in metals For combinations of metals satisfying all three conditions, alloys with a single homogenous solid phase (having well defined crystal structure) are formed at all compositions. Such alloys are called continuous solid solutions. For example, alloys of Cu and Ni. Given below is a list of metals with their size and crystal structure Metal Cu Ni Cr K Pb Al Ag Au Zn Crystal Structure fcc fcc bcc bcc fcc fcc fcc fcc hcp Atomic radii (in Å) 1.28 1.25 1.29 2.27 1.75 1.43 1.44 1.44 1.37 1.1 For the following combinations of metals, identify if it can form a continuous solid solution.

Yes No Cu & Ag

Cr & K

Cu & Al

Ag & Al

If only one or two of the conditions I-III are satisfied, two or more homogenous phases (each having different structure and properties) may form at different compositions. At a given composition, an alloy may exist as a single phase, or two phases may co-exist within the material. As we heat the alloy, the solid phase(s) can melt above a certain temperature and co-exist with the corresponding liquid over a temperature range and then get converted into pure liquid phase. This information of thermodynamically stable phases of different alloy compositions and at different temperatures is represented in a phase diagram. Phase diagram of Cu and Zn alloys, commonly known as brass, is shown in Fig. 1. In the diagram, each area marked by solid boundaries represents a phase or a mixture. For example, regions marked by $\alpha$, $\beta$, $\gamma$, etc., represent different solid phases of brass, i.e., $\alpha -brass$, $\beta -brass$, etc. The regions between these two areas (not labelled) represent a mixed phase of two adjoining single phases like $\alpha$ + $\beta -$ brass.

Fig 1. Phase Diagram of Cu-Zn Adapted from: Journal of Hazardous Materials, Sep 2013, 262C:606-613

100% Zn 100% Cu Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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1.2 Consider a brass with 30% Cu by mass. Identify the phase/phases that it will adopt at 300 oC and 750 oC, respectively.

Varieties of brass have wide importance because of their mechanical, chemical, electrical, and acoustic properties. Change in these properties and colours can be achieved by variation in the composition of the two metals as well as by the addition of other metal atoms to some extent. Brass with low zinc percentages is used for musical instruments. Higher concentration of Zn atoms (being larger in size) reduces the mobility of Cu atoms, making the alloy harder. Thus, $\beta$ and $\gamma$ phases are more appropriate for making machine parts. To find out the percentage of different metals, the alloy sample needs to be converted to soluble form. A brass sample was dissolved using conc. H2SO4 (with catalytic amount of conc. HNO3) to prepare a sample solution X, which was given to two labs for independent analysis. The first lab used iodometric titration to determine the amount of Cu and complexometric titration to determine the total Cu + Zn content. 1.3 i) In the iodometric titration, I– ions (present in excess) act as reducing and precipitating agent. Write balanced chemical equation for this reaction.

ii) The I2 liberated during this reaction is titrated with sodium thiosulphate. Complete and balance the given equation for the reaction.

I2 (aq) + Na2S2O3(aq) $\to$ Na2S4O6 (aq) + ___________ iii) Determine the magnetic moment of the precipitate formed in 1.3 i).

iv) The colour of precipitate formed in 1.3 i) is (Mark X for the correct answer)

a) white

b) deep blue c) reddish pink

v) A 10.0 mL of solution X when titrated iodometrically, consumed 6.9 mL of 0.104 M sodium thiosulphate solution. The same amount of solution X was titrated at pH 5.5 (using an acetate buffer) with 0.095 M EDTA (ethylene diamine tetra acetate) using xylenol orange indicator. The titration required 10.5 mL of EDTA till the end point. In this titration, both Cu and Zn form a 1:1 complex with EDTA. Calculate the % of Zn in the sample.

vi) Identify the type of brass sample using the phase diagram in Fig. 1.

vii) This brass sample would be useful for making (Mark X against the correct option(s))

a) ghungroo (sound making hollow balls)

b) trumpet/flute c) locks

d) hinges for doors and windows The second lab that received this sample solution X, used cupron (structure given below) which selectively complexes only with Cu(II) giving a precipitate.

1.4 i) 50 mL of solution X mixed with excess of cupron gave a precipitate of Cu(cupron)y which on drying weighed 1.86 g. Determine the value of y.

ii) The filtrate obtained in 1.4 i) (after filtering the Cu(cupron)y precipitate) was treated with excess of (NH4)2HPO4 in ammoniacal solution, which precipitates zinc ammonium phosphate. The precipitate was filtered and dried at room temperature. Then the anhydrous precipitate was heated at 900oC eliminating ammonia and water to get zinc pyrophosphate. Write a balanced chemical equation for the pyrolysis reaction.

Cupron Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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iii) Determine the mass of zinc pyrophosphate obtained.

Brass is used in making bells because it is sonorous like silver, i.e., when hit with a hard object, it produces deep or resonant sound. Sonority requires the material to have free mobile electrons. In addition, the material must have moderate density and hardness such that the kinetic energy can be translated into sound waves, and the latter can be propagated by the free electrons within. 1.5 Which of the following can also be sonorous?

a) sodium

b) copper

c) iron d) mercury

e) diamond

Some brass samples contain small amounts of other metals such as Ni, Pb, or As. A solution of nickel brass (containing Ni in addition to Cu and Zn) prepared by dissolving in nitric acid, was reacted in separate beakers with NaOH (aq) and NH3 (aq), respectively. In both beakers, stable precipitates were observed. The pH of the supernatant containing ammonia was 9.5. 1.6 Write the metal ion(s) and their form (ions/complex/compound) present in the supernatant and the composition of the precipitate in the two reactions in the following table:

Reaction Metal ion(s) and their form in the supernatant Composition of precipitate Ni-brass solution + excess NaOH (aq.)

Ni-brass solution

• excess NH3 (aq.) till pH is 9.5

1.7 Metalloenzymes have proteins with various amino acid side groups providing suitable coordination environment for the metal ions at the active sites. A protective enzyme superoxide dismutase (SOD) contains Cu2+ and Zn2+ at its active sites and hence, is aptly called as “Brass Enzyme”. The active center in SOD has a metal binding site with near-square-planar coordination geometry (site A) and another with tetrahedral coordination geometry (site B). i) Which metal ions occupies site A and B, respectively?

The active site undergoes a reversible redox reaction during the dismutation (simultaneous oxidation and reduction) of superoxide, which can be represented as 2O2 ‒ $\to$ O22‒ + O2 ii) Write the metal ion actively participating in the catalytic reaction.

Topic: Conservation of Energy, Oscillations & Waves, Thermodynamics Metodi: Energy Conservation Method, Conservation Laws, Simple Harmonic Motion Analysis, Wave Equation Competenze: Physical Reasoning, Mathematical Modeling Fonte: Testo (PDF) — p.2

Problema 2

Problem 2

25 marks Hydrogen Peroxide- a Versatile Reagent Hydrogen peroxide, H2O2 is an important chemical widely used in households as well as industry. Dilute solutions of H2O2 are used as domestic disinfectants and anti-septic agents. It is used as a bleaching agent in textile, paper, food and pharmaceuticals industries. This problem consists of two parts- Part I is about some chemical properties of hydrogen peroxide which make it highly useful, and Part II is on use of H2O2 for metal recovery from spent catalysts. Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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Part I: Chemical Properties of H2O2 2.1 When H2O2 is mixed with a base, it forms a new ion, A. i) Draw the Lewis structure of A. ii) Write balanced equation for the formation of A.

2.2 H2O2 is a weak acid (pka = 11.75). Determine the pH of 3% (w/w) aqueous solution of H2O2 (density = 1.01 g cm‒3).

2.3 When H2O2 is mixed with a dilute solution of H2SO4, it forms solution X in which H2O2 is converted to species B. i) Draw the Lewis structure of B. ii) Write balanced equation for formation of B.

2.4 Write the balanced equations for the following two reactions.

i) When solution X is mixed with another colorless solution, it resulted in a yellow-brown color solution which developed dark blue color on the addition of starch. ii) When solution X is mixed with a Mn-containing solution having deep violet color, it resulted in decolorization of the solution.

Part II: Recycling of Spent Catalyst

Crude petroleum and natural gas usually contain sulphur compounds which are removed industrially using catalysts containing Mo, Co, and Ni, and their oxides supported on alumina. This process is called hydrodesulfurization (HDS). After many cycles, these catalysts lose their activity due to formation of their respective sulphides and are disposed in landfills. However, metals can be recovered from these spent catalysts. For effective recovery, these materials are ground into fine powder. Extraction of metals from this powder can be done by two methods: • Roasting + Leaching: The powdered catalyst is heated in an open furnace at 850 ${}^{\circ }C$ in presence of air. The metal sulphides get converted to oxides with 95% conversion. The oxides are then leached using H2SO4. • Direct Leaching (without roasting): Hydrogen peroxide (30%) and sulfuric acid are used directly to dissolve the metal sulphides. Typically, 89% of the metal sulphides get dissolved in this method. A flow diagram of the two processes is shown below.

Fig. 1 Flow diagram of dissolution process of spent catalyst

Subsequently, individual metals are extracted from the leach solutions using the following process. Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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Fig. 2 Flow diagram of metal separation from leach solution

2.5 A metallurgical plant received 10 kg of spent catalyst powder (Mo = 8.72%, Co = 1.97%, Ni = 1.04%) to recover metals. As a trial, one staff tried roasting method for 1 kg of the catalyst. Molybdenum sulphide gets oxidized as per the following chemical reaction. 2MoS2 + 7O2 $\to$ 2MoO3 + 4SO2(g) i) Write balanced equations for the roasting of Co and Ni sulphides (where Co remains in +2 oxidation state under the roasting condition).

ii) Determine the volume of SO2 released in the above process at the furnace temperature and atmospheric pressure.

2.6 Another staff dissolved 1 kg catalyst using the direct leaching method, by using 1 kg of 15% w/w H2SO4 solution and stoichiometrically equivalent amount of hydrogen peroxide (30% w/w solution). The H2SO4 predominantly helps dissolving metal sulphides. Note that 89% of the metals in the catalyst get dissolved. The balanced equations for reactions during dissolution of metal sulphides are given below.

MoS2 (s) + 9H2O2 (aq) $\to$ MoO22+(aq) + $2SO42-$ (aq) + 8H2O + 2H+(aq)

CoS (s) + 4H2O2 (aq) $\to$ Co2+(aq) + $SO42-(aq$) + 4H2O NiS (s) + 4H2O2 (aq) $\to$ Ni2+(aq) + $SO42-(aq$) + 4H2O

i) Calculate the molality of Mo obtained in this solution.

ii) Identify the major species present in the final filtrate obtained at the end of Step 3 of metal extraction. (Assume that each precipitating reagent was added about 5% in excess and the metal precipitations were complete).

iii) The final filtrate is concentrated by boiling. Identify the compound which can be recovered in largest amount from this process.

iv) After concentration and separation of solids, remaining filtrate can be added back to one of the steps (1 or 2 or 3) shown in Fig 2., with a specific advantage. In the table below, mention this step number in Row I, and the advantage(s) in appropriate column(s) in that row. In Row II, mention disadvantage(s) if it is added in any one of the other steps.

4 Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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reduces consumption of enhances yield of decreases contamination in increases contamination in I. When added in the chosen step ____,

II. When added in another step ____,

2.7 The advantage of hydrogen peroxide leaching over roasting + leaching process is (mark X in box for the applicable statement(s) and for marked statements, write the appropriate substances in the blank spaces). a) It prevents formation of _________ as waste product. b) It enhances formation of ________ as a useful by-product. c) It reduces consumption of ________ as input chemicals.

Topic: Thermodynamics, Astrophysics Metodi: First Law of Thermodynamics, Thermodynamic Cycle Analysis, Ideal Gas Law, Newton’s Law of Gravitation Competenze: Mathematical Modeling, Estimation & Approximation Fonte: Testo (PDF) — p.4

Problema 3

Problem 3

21 Marks Structure Elucidation of a Drug

Determining the structure of an active component from natural sources (such as plants and microorganisms) which acts as a drug/medicine can help to produce it on a large scale. In this question, we will work out the structure of a drug (A) isolated from a natural source. Analytical experiments indicate that A is a heterocyclic compound with molecular formula C16H18O4N2S. Compounds with free thiol (-SH) group give strong colours when treated with aqueous FeCl3. A does not give color when reacted with aqueous FeCl3. 3.1 A gives effervescence with a solution of sodium bicarbonate and forms a mono-sodium salt. When A is treated with nitrous acid, no gas is evolved. From these observations, the inference that can be drawn is that molecules of A have (Mark X for the correct option(s))

a) presence of -COOH and -NH2 groups. b) presence of -COOH, phenolic -OH and absence of -NH2 groups. c) presence of -COOH and absence of -NH2 groups. d) presence of phenolic -OH and absence of -NH2 groups. On hydrolysis with hot dilute hydrochloric acid, A gives B (C5H11O2NS) and C (C10H11O2N) as shown in the following reaction.

3.2 Compound B can be synthesized in the lab via the following steps. Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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i) Draw the structures of the major products D and E.

ii) Among the following, identify the correct structure of intermediate E’ formed in the above reaction scheme. (Mark X against the correct option)

iii) Draw the structures of intermediate F and products G and B.

iv) pH metric titration of compound B showed three pKa values 1.8, 7.9 and 10.5. Write the functional groups present in molecules of B corresponding to these pKa values.

In a class, two teams of students were given compound B for functional group analysis. Team 1 students dissolved compound B in water while team 2 students dissolved it in acetone. Both teams treated their solutions of B with aqueous FeCl3 and with nitrous acid separately. Students of one of the two teams could observe color change with aqueous FeCl3 and nitrogen gas evolution with nitrous acid, while students of the other team did not obtain these two observations. v) Identify the team that got reaction(s) with the two reagents, and the correct statement(s) from the options given below (a-e) explaining the results of Team 1 and Team 2.

a) B got hydrolyzed in water. b) B reacted with acetone. c) B got dissolved in water thus gave positive results for functional group analysis. d) B did not dissolve in acetone and thus could not give results for functional group analysis. e) B did not dissolve in water and thus could not give positive result. 3.3 Compound C on heating with concentrated HCl gives phenylacetic acid and $\alpha -amino$ acetaldehyde. Write the structure of C.

3.4 Drug A can also be synthesized from B through the following route.

i) Draw the structures of H, I, K and L. Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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A can be obtained from L by reacting it with Dicyclohexylcarbodiimide (DCC).

DCC is a common reagent used to combine amino acids in peptide synthesis. The general mechanism of the above reaction with DCC is as given below.

ii) Draw the structures of M, N, O, P and Q. iii) Draw the structure of A.

iv) An ideal drug molecule must have both polar and non-polar groups. Polar groups are required for its transport through blood while non-polar groups ensure crossing of the drug molecule through the lipid cell membrane. Redraw the structure of drug A and draw circles around the polar groups and draw rectangles around the non-polar parts of the molecule.

Topic: Conservation of Energy, Thermodynamics Metodi: Energy Conservation Method, Conservation Laws, First Law of Thermodynamics, Thermodynamic Cycle Analysis Competenze: Physical Reasoning, Mathematical Modeling Fonte: Testo (PDF) — p.7

Problema 4

Problem 4

24 marks An acid from sugar

A compound (A) named as hexuronic acid was isolated from Hungarian Paprika (Capsicum annuum). A is a white to very pale-yellow crystalline powder with a sharp acidic taste. It is a carbohydrate derivative with the following structure:

A

4.1 Draw other possible stereoisomers for A.

4.2 Molecules of A exhibit tautomerism. Draw all the tautomeric forms of A.

An experimentalist prepared 0.10 M solution of compound A and found its pH to be 2.6. Its second acid dissociation constant, pKa2 was found to be 11.4. 4.3 Calculate pKa1 of A. Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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4.4 Draw the structure of the predominant ionic forms of A with correct stereochemistry (its bioactive form) present at i) physiological pH 7.3 and ii) pH 12.0.

A reacts rapidly with diazomethane, giving derivative B (C8H13O6). On reaction with reagent X, B gives formaldehyde as one of the products. 4.5 Give the structure of B and molecular formula of the reagent X.

B on further treatment with moist Ag2O and CH3I forms C. Action of ozone on C yields a neutral compound D which on elemental analysis gave 48.38% carbon and 6.45% hydrogen.

4.6 Derive the molecular formula of D and draw the structures of C and D. Show all the calculations involved in the derivation.

4.7 The reaction of moist Ag2O + CH3I with B proceeds via (Mark X for the correct option):

a) nucleophilic substitution

b) nucleophilic addition c) electrophilic addition

d) electrophilic substitution 4.8 In the given reaction, moist Ag2O is acting as a (Mark X for the correct option):

a) source of nucleophile

b) source of electrophile

c) acid d) base

e) amphoteric initiator A, on mild oxidation by iodine under aqueous acidic conditions gives a compound E (C6H6O6). If (A) is oxidized using sodium hypoiodite in alkaline solution, oxalic acid and a monobasic acid F are formed. F on further oxidation yields tartaric acid (C4H6O6). 4.9 Draw the structures of E and F. If the structure(s) is/are acyclic, draw it using Fischer Projection.

A cannot be produced by humans, and hence, it must be obtained through diet. But some other species can convert D-glucose into A by a biochemical pathway. In this biochemical conversion, D-Glucose is first oxidized to a compound G having 57.70% oxygen. 4.10 Choose the correct structure of G from the following (Mark X for the correct option):

Under physiological conditions, G is converted to a compound H (C6H8O6), which undergoes reduction to yield a compound I. Finally, I undergoes dehydrogenation to produce A. 4.11 Draw the structures of H and I with correct stereochemistry.

A is a powerful enhancer of non-heme iron absorption and is used in the treatment of anaemia. It reacts with Fe3+ ions to form an octahedral complex having a molecular formula [C12H16FeO14]–. 4.12 Draw the structure of the iron complex of A.

•OH is the most reactive of all the ROS (reactive oxygen species) and interacts with DNA causing its damage. The bioactive form of compound A (the form at physiological pH) reacts with •OH through a single electron Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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transfer to form J and K. On subsequent deprotonation, J yields a stable radical L, which does not cause DNA damage. 4.13 Draw the structures of J, K and L.

A is estimated in food substances by titrating it with ceric ammonium sulphate which acts as a one electron oxidizing agent. 4.14. Write the product in the given equation for the above titration and balance it.

A + Ce(NH4)4(SO4)4 E +

Topic: Nuclear & Particle Physics Metodi: Radioactive Decay Law, Mass-Energy Equivalence, Conservation Laws Competenze: Mathematical Modeling Fonte: Testo (PDF) — p.9

Problema 5

Problem 5

16 marks The purple hydrogen

When high voltage is applied to hydrogen gas enclosed in an electric discharge tube, it gives a purple glow. In nature, such colour can be observed in light coming from some stars. Origin of this colour in hydrogen remained a mystery for long. In an experiment in the 19th century, scientists passed the light from a hydrogen discharge tube through a slit followed by a glass prism. On a screen kept behind the glass prism, multiple lines could be seen with a very bright red line followed by a blue and few closely spaced violet lines. In experiments in early 20th century when diffraction grating was used instead of glass prism, few additional lines could be detected as non-visible extensions of the spectrum as shown below.

Spectrum S1

Spectrum S2 In later experiments, several more lines at higher wavelengths were detected in the spectrum of hydrogen discharge, but no lines were detected at wavelengths lower than those seen in spectrum S2. 5.1 Each of these lines originated from a specific decrease in energy of hydrogen atoms as the atoms transitioned from one well-defined energy state to another. Determine the frequency of light originating from the lowest energy transition observed in spectrum S2.

The wavelengths obtained in the above spectra were analyzed by many mathematicians. Finally, it was recognized that the wavelengths corresponded to change in energy states of hydrogen atom, where energy of each state would be of the form En = ‒ C/n2, where C is a constant and n is a natural number. 5.2 i) Using the wavelength data in S1 and S2, determine the value of C in Joules and in cm‒1. Give detailed steps followed to obtain the answers.

ii) Determine the n values for states, transitions between which produces light of wavelengths 102.6 nm and 434.0 nm. Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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According to the Bohr atomic model, electrons in an atom move in circular orbits around the nucleus (as depicted in the figure). The hydrogen atom is stable because the magnitude of the centrifugal force 2 m r

and electrostatic force 2 2 0 4 Ze r

at distance, a0 are equal. 5.3 Find the magnitude of velocity of the electron in hydrogen atom and find its ratio to the speed of light.

Imagine that we can capture snapshots of the electron orbiting in the circular path. Four representative snapshots among several are illustrated below:

Alternatively, several snapshots can be collectively represented in a single figure as given on the right-hand side image. This figure shows that the probability of finding the electron on the orbit of radius r = a0 is 100% (according to the Bohr model).

On the contrary, different experiments collectively exhibit the following superimposed snapshots for the position of the electron in a hydrogen atom. Here, the nucleus is located at the origin and position of the electron (shown by dots) can be anywhere around the nucleus; however, there are regions where the electron is found more frequently than the other regions.

Quantum mechanical model provides a possible explanation for the above experimental realization using a mathematical function, called the probability density function. The probability density of the electron in hydrogen atom or hydrogen like atoms/ions (with atomic number Z) in lowest energy state at a distance r obtained from quantum mechanical model, can be expressed as: f(r) = 4Z3 a0 3 r2e $-$ 2Z r a0 This function for hydrogen is plotted in the following figure: Indian National Chemistry Olympiad 2025 ©HBCSE February 1, 2025

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5.4 Find the most probable value of r (the distance from the origin where the probability density of finding the electron is maximum) for a hydrogen atom.

5.5 Based on the most probable value of r, possible true statements among the following is/are (Mark X for the correct option(s)):

a) Bohr model predicted locations of electron which are impossible in reality. b) In quantum mechanical model, circular motion is not possible, only linear motion is possible. c) In quantum mechanical model, electron motion is not possible. d) In quantum mechanical model, electron in lowest energy state can be found at a distance r = 8a0. 5.6 Curves representing the ground state probability density functions of electron in H atom, He+ ion and Li2+ ion are given in diagram below. Identify which curve corresponds to which specie.

Assume that a specially designed hydrogen discharge lamp DL creates excited hydrogen atoms in n = 2 state only. Electronically excited atoms finally transition back to the ground state by emitting photons with appropriate frequency. One can monitor the emission intensity, I at any given time, t , using a photosensitive detector. Assume that at time 0 t = (i.e., when the excited hydrogen atoms were generated), the emission intensity was I0. Change of emission intensity as a function of time can be expressed by the following rate equation: dI kI dt $-$

; where, 8 10 k = s‒1 for n = 2 $\to$ n = 1 transition and depends on the electron distribution in the initial and final states. 5.7 Find the time at which the intensity of discharge lamp drops to 10% of the initial intensity after it is switched off.

5.8 Identify the colour of emission of this discharge lamp DL.

r 1 H hydrogen 1.008 [1.0078, 1.0082] 1 18 3 Li lithium 6.94 [6.938, 6.997] 4 Be beryllium 9.0122 11 Na sodium 22.990 12 Mg magnesium 24.305 [24.304, 24.307] 19 K potassium 39.098 20 Ca calcium 40.078(4) 37 Rb rubidium 85.468 38 Sr strontium 87.62 38 Sr strontium 87.62 55 Cs caesium 132.91 55 Cs caesium 132.91 56 Ba barium 137.33 87 Fr francium 88 Ra radium 5 B boron 10.81 [10.806, 10.821] 13 Al aluminium 26.982 31 Ga gallium 69.723 49 In indium 114.82 81 Tl thallium 204.38 [204.38, 204.39] 6 C carbon 12.011 [12.009, 12.012] 14 Si silicon 28.085 [28.084, 28.086] 32 Ge germanium 72.630(8) 50 Sn tin 118.71 82 Pb lead 207.2 7 N nitrogen 14.007 [14.006, 14.008] 15 P phosphorus

30.974 33 As arsenic 74.922 51 Sb antimony 121.76 83 Bi bismuth

208.98 8 O oxygen 15.999 [15.999, 16.000] 16 S sulfur 32.06 [32.059, 32.076] 34 Se selenium 78.971(8) 52 Te tellurium 127.60(3) 84 Po polonium 9 F fluorine 18.998 17 Cl chlorine 35.45 [35.446, 35.457] 35 Br bromine 79.904 [79.901, 79.907] 53 I iodine 126.90 85 At astatine 10 Ne neon 20.180 2 He helium 4.0026 18 Ar argon 39.95 [39.792, 39.963] 36 Kr krypton 83.798(2) 54 Xe xenon 131.29 86 Rn radon 22 Ti titanium 47.867 22 Ti titanium 47.867 40 Zr zirconium 91.224(2) 72 Hf hafnium 178.49(2) 104 Rf rutherfordium

23 V vanadium 50.942 41 Nb niobium 92.906 73 Ta tantalum 180.95 105 Db dubnium 24 Cr chromium 51.996 24 Cr chromium 51.996 42 Mo molybdenum 95.95 74 W tungsten 183.84 106 Sg seaborgium 25 Mn manganese 54.938 43 Tc technetium 75 Re rhenium 186.21 107 Bh bohrium 26 Fe iron 55.845(2) 44 Ru ruthenium 101.07(2) 76 Os osmium 190.23(3) 108 Hs hassium 27 Co cobalt 58.933 45 Rh rhodium 102.91 77 Ir iridium 192.22 109 Mt meitnerium 28 Ni nickel 58.693 46 Pd palladium 106.42 78 Pt platinum 195.08 110 Ds darmstadtium 29 Cu copper 63.546(3) 47 Ag silver 107.87 79 Au gold 196.97 30 Zn zinc 65.38(2) 48 Cd cadmium 112.41 80 Hg mercury 200.59 111 Rg roentgenium 112 Cn copernicium 114 Fl flerovium 113 Nh nihonium 115 Mc moscovium 117 Ts tennessine 118 Og oganesson 116 Lv livermorium 57 La lanthanum 138.91 58 Ce cerium 140.12 59 Pr praseodymium 140.91 60 Nd neodymium 144.24 61 Pm promethium 62 Sm samarium 150.36(2) 63 Eu europium 151.96 64 Gd gadolinium 157.25(3) 65 Tb terbium 158.93 66 Dy dysprosium 162.50 67 Ho holmium 164.93 68 Er erbium 167.26 69 Tm thulium 168.93 70 Yb ytterbium 173.05 71 Lu lutetium 174.97 89 Ac actinium 90 Th thorium 232.04 91 Pa protactinium 231.04 92 U ura

Topic: Modern-Quantum Physics, Oscillations & Waves Metodi: Bohr Model & Quantization, Photon Energy Relation, Differential Equations Competenze: Mathematical Modeling, Physical Reasoning, Graph Linearization Fonte: Testo (PDF) — p.11