Inorganic Chemistry - Problem Drill 16: The d and f Elements

Question No. 1 of 10 Instructions: (1) Read the problem statement and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed.

The series (4f) of chemical elements comprises the fifteen metallic chemical elements with atomic numbers 57 through 71. Which element is not generally classified with the ?

A. La B. Lu C. U

Question D. Gd E. Nd

A. Incorrect! La is generally included as the first element in the lanthanide series, despite having no electrons in the f- orbital, since the properties are similar to the f-block lanthanide series (6s2, 5d1).

B. Incorrect! Lu is the last element in the lanthanide series and has a fully filled f-orbital (5d14f14).

C. Correct! U belongs to the (5f) series of elements.

Feedback D. Incorrect! Gd has a 4f7 . Hence, belongs with the lanthanide series of elements.

E. Incorrect! Nd has a 4f4 electron configuration. Hence belongs to the lanthanide series of elements.

Correct answer: U

Uranium belongs to the 5f-block of elements, known as the . The actinides are classified together since they have similar properties.

Solution

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Titanium is a with symbol Ti and 22. It is a lustrous transition with a color. Which statement is not true on a property or application of Ti?

A. Ti has high strength and low mass compared with steel. B. Ti does not react with .

Question C. Ti is used in aerospace industry. D. Rutile is a mineral of Ti. E. Ti is resistant to corrosion.

A. Incorrect! Ti is used in applications which require a low mass to strength ratio (e.g., air craft engines).

B. Correct! This is a false statement. Ti is forms tetrahalides (TiCl4).

C. Incorrect! Due to its high strength and low mass it is used in the aerospace industry.

D. Incorrect! Feedback Rutile has the formula TiO2 and is a mineral of Ti.

E. Incorrect! Ti is a corrosion resistant material.

Correct Answer B. Ti does not react with halogens. This statement is not true. does react with the halogens upon warming to form titanium(IV) halides.

Ti is known for its high strength and low density. Solution

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Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in 6. It is a steely-gray, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point. Which of the following is not a property or application of group 6 element Cr?

A. Cr has an electron configuration 4s23d4. B. is used in the electroplating industry.

Question C. The presence of Cr gives red color to the gem ruby. D. Chromite is a mineral containing Cr. E. Chromium is used in alloys.

A. Correct! Cr and Mo does not show the expected electron configuration of 4s23d4, instead prefers the 4s13d5 configuration as it is more stable with half-filled per Hund’s rule.

B. Incorrect! Chromium plating is used for decorative purposes and to increase surface hardness of other materials.

C. Incorrect! The red color of ruby is due to the presence of Cr. Most transition elements are colored due to d-d transitions.

Feedback D. Incorrect! Chromite is an chromium oxide (FeCr2O4). It is indeed a chromium oxide mineral.

E. Incorrect! Chromium is alloyed with Fe in certain steel materials.

Correct answer A. Cr has an electron configuration 4s23d4.

Cr and Mo do not show the expected electron configuration of 4s23d4, instead, prefers the 4s13d5 configuration. This is in according to the Hund’s Rule - Every orbital in a sublevel is singly occupied Solution before any orbital is doubly occupied.

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Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in combination with iron, and in many minerals. is a metal with important industrial metal alloy uses, particularly in stainless steels. Which of the following is not an application or property of group 7 metal Mn?

A. Mn is used as cathode material in dry cell batteries. B. Common mineral of Mn is pyrolusite (MnO2). Question C. Mn can form compounds with +7 . D. Mn is the most abundant group 7 element. E. Mn compounds are white in color.

A. Incorrect! This is a true statement. MnO2 is a part of cathode material in dry cell batteries.

B. Incorrect! This is indeed a common mineral of Mn.

C. Incorrect! This is a true statement. Mn has seven electrons (4s23d5).

D. Incorrect! Feedback The other group 7 elements (Tc and Re) are found only in trace amounts in nature.

E. Correct! Mn is a , containing partially filled d-orbitals. Transition metal compounds are generally colored due to d-d and/or metal-ligand transitions. Aqueous solution of KMnO4 has the deep purple of Mn(VII) as it occurs in permanganate.

Correct answer E. Mn compounds are white in color.

Mn is a transition metal, containing partially filled d-orbitals. Transition metal compounds are generally colored due to d-d and/or metal-ligand transitions. The most stable oxidation state for manganese is +2, which has a pale pink color. Permanganate (+7 oxidation state) compounds are purple, and can give Solution glass a violet color.

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Group 8 consists of iron (Fe), (Ru), (Os) and (Hs). They are all transition . Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior. Which of the following is not a property or application of Group 8 elements, Fe, Ru and Os?

A. Ru has a different d-electron configuration than Fe and Os. B. Osmium is one of the densest elements. C. Fe is isolated by reduction of Fe2O3 by CO. Question D. All elements of group 8 also belong to the Pt group metals and are equally reactive. E. Fe plays a role in the binding and activation of in biological enzymes and proteins.

A. Incorrect! This is a true statement. Ru has an s1d7 electron configuration, whereas, Fe and Os have the expected s2d6 electron configuration.

B. Incorrect! Osmium is the densest naturally occurring element. The density of Os is 22.5 g/cm3.

C. Incorrect! Fe is isolated by the reduction of Fe2O3 (hematite mineral) by the following reaction: Fe2O3 + 3 CO  2 Fe + 3 CO2

Feedback D. Correct! Fe does not belong to the Pt group of metals. The Pt group metals include Ru, Os, Rh, Ir, Pd and Pt which are all clustered together in the and exhibit similar properties.

E. Incorrect! Fe is the central metal in hemoglobin which binds and transports molecular oxygen.

Correct answer D. All elements of group 8 also belong to the Pt group metals and are equally reactive.

Fe does not belong to the Pt group of metals. The Pt group metals include Ru, Os, Rh, Ir, Pd and Pt which are all clustered together in the periodic table and exhibit similar properties.

Solution

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Group 9, numbered by IUPAC nomenclature, is a group of chemical element in the periodic table. Members are (Co), (Rh), (Ir) and (Mt). These are all transition metals in the d-block. All known of meitnerium are radioactive with short half-lives, and it is not known to occur in nature. Which of the following is not a property or application of group 9 elements Co, Rh and Ir?

A. Rh has a different d-electron configuration than Co and Ir.

Question B. Co is found in vitamin B-12. C. Rh and Ir are one of the most abundant elements on earth. D. Rh complexes are used as homogeneous catalyst. E. Radioactive is used as a source of gamma rays.

A. Incorrect! Rh has the electron configuration [Kr]5s14d8, which is different from the expected configuration s2, d7 shown by Co and Ir.

B. Incorrect! Co is part of the Vitamin B-12 structure and is a class of Co containing compounds known as cobalamines.

C. Correct! This is a false statement. Rh and ir are one of the rarest elements found in the earth’s crust.

Feedback D. Incorrect! Wilkinson’s catalyst is a Rh complex which is used to catalyze the hydrogenation reactions of alkenes.

E. Incorrect! 60Co is radioactive and is a source of gamma rays.

Correct answer: C. Rh and Ir are one of the most abundant elements on earth.

This is a false statement. Rh and ir are one of the rarest elements found in the earth’s crust. All group 9 elements are relatively rare in the earth's crust, with the most abundant, cobalt, only accounting for 0.0029% of the Earth's crust. Rhodium and iridium are two of the rarest naturally occurring elements in the earth, only found in ores. Solution

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A halide is a binary compound. Transition-metal compounds are often colored. The color results from the transition of electrons between the two closely spaced d-orbitals. The transitions are due to the electric field of the compound's ligands. Which ion forms colorless compounds with halides?

A. Zn2+ B. Mn2+ Question C. Cr3+ D. Co2+ E. Fe3+

A. Correct! Zn2+ has a fully filled d10 electron configuration. Transition metal ions are generally colored due to d-d electronic transitions. This is only possible if vacant d-orbitals are present for excitation.

B. Incorrect! The d-d transitions are possible in ions containing partially filled d-electron configurations.

C. Incorrect! The d-d transitions are possible in ions containing partially filled d-electron configurations.

D. Incorrect! Feedback The d-d transitions are possible in ions containing partially filled d-electron configurations.

E. Incorrect! The d-d transitions are possible in ions containing partially filled d-electron configurations.

Correct answer A. Zn2+

Zn2+ has a fully filled d10 electron configuration. Transition metal ions are generally colored due to d-d electronic transitions. This is only possible if vacant d-orbitals are present for excitation. The partially full d-orbitals in transition metals have energy splittings that happen to lie in the visible range.

Solution

RapidLearningCenter.com  Rapid Learning Inc. All Rights Reserved Question No. 8 of 10 Instructions: (1) Read the problem statement and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. Group 10, numbered by current IUPAC style, is the group of chemical elements of d-block transition metals. Group 10 metals are white to light grey in color, and possess a high luster, a resistance to tarnish (oxidation). They are highly ductile. Which of the following is not true regarding group 10 elements Ni, Pd and Pt?

A. They are used as catalyst. B. Pt is an extremely reactive element. C. Pt and Pd are used in catalytic converters in automobiles. Question D. Pd strongly adsorbs gas. E. The common oxidation states are +2 and +4.

A. Incorrect! This is a true statement. Pt and Pd are popular catalyst for hydrogenation reactions.

B. Correct! The elements of Pt group metals are generally un-reactive.

C. Incorrect! Catalytic converters covert toxic or harmful gases emitted from automobile engine to less harmful products. Pt and Pd are widely used for this purpose.

Feedback D. Incorrect! Pd metal strongly adsorbs hydrogen gas. Hence is investigated as a potential hydrogen storage device.

E. Incorrect! The common oxidation states are +2 and +4 (+1 and 0 oxidation states are also known).

Correct answer B. Elements of group 10 are extremely reactive.

Pt and Pd are resistant to corrosion and other reactions. Hence, Pt is used in fine jewelry.

Solution

RapidLearningCenter.com  Rapid Learning Inc. All Rights Reserved Question No. 9 of 10 Instructions: (1) Read the problem statement and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. Organocobalt chemistry is the chemistry of organometallic compounds containing a to cobalt chemical bond. Which of the following is a cobalt containing biomolecule?

A. Hemoglobin B. Myoglobin C. Cytochrome c oxidase D. Vitamin B12 Question E. Nitrogenase

A. Incorrect! Hemoglobin is an oxygen carrying protein containing Fe.

B. Incorrect! Myoglobin is an oxygen carrying protein containing Fe.

C. Incorrect! Cytochrome c oxidase is involved with the reduction of dioxygen and contains Fe and Cu.

Feedback D. Correct! Vitamin B12 consists of a class of chemically related compounds, all of which have vitamin activity. It contains the biochemically rare element cobalt.

E. Incorrect! Nitrogenase is a plant enzyme, which catalyses the fixation of atmospheric to ammonia.

Correct answer D. Vitamin B12

Organocobalt chemistry is the chemistry of organometallic compounds containing a carbon to cobalt chemical bond. Organocobalt compounds are involved in several organic reactions and the important biomolecule vitamin B12 has a cobalt-carbon bond. Vitamin B12 is a cobalt containing vitamin, which is useful for the function of brain and nervous systems and belongs to a class of cobalt compounds called

Solution cobalamines.

RapidLearningCenter.com  Rapid Learning Inc. All Rights Reserved Question No. 10 of 10 Instructions: (1) Read the problem statement and answer choices carefully, (2) Work the problems on paper as needed, (3) Pick the answer, and (4) Review the core concept tutorial as needed. Which isotope is used in nuclear fission reactors?

A. 2H B. 82Pt C. 92Kr D. 238U E. 235U Question

A. Incorrect! Deuterium does not undergo nuclear fission.

B. Incorrect! 82Pb is a stable nuclei and is the end product of the series.

C. Incorrect! 92Kr is not an isotope which is applicable in fission reactors.

D. Incorrect! 238 U is not an isotope which is applicable in fission reactors. Feedback

E. Correct! 235U can be fragmented by bombardment with neutrons. Fission results in release of thermal energy and more neutrons. The released neutron can be used to create a controlled chain reaction with release of more thermal energy.

Correct answer E. 235U

235U can be fragmented by bombardment with neutrons. Fission results in release of thermal energy and more neutrons. The released neutron can be used to create a controlled chain reaction with release of more thermal energy.

Solution

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