Transition Elements and d Orbitals

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Questions and Answers

What is the product when potassium iodide reacts with permanganate in acid solutions?

Sulfate

Nitrite

Oxalate

Iodine (correct)

Which ion is produced from the oxidation of ferrous ion by permanganate?

Fe3+ (correct)

Mn2+

Mn3+

Fe2+

At what temperature is oxalic acid oxidized by permanganate in the given reaction?

333 K (correct)

353 K

303 K

293 K

What is the main product when hydrogen sulfide is oxidized by permanganate?

Sulfur Signup and view all the answers

What is the final product when nitrite is oxidized by permanganate?

Nitrate Signup and view all the answers

What characteristic property is NOT exhibited by transition metals?

Completely filled d orbitals Signup and view all the answers

Why does scandium (Z = 21) qualify as a transition element while zinc (Z = 30) does not?

Scandium has incompletely filled 3d orbitals. Signup and view all the answers

Which of the following statements is true about transition metals?

They can form complexes with a variety of ligands. Signup and view all the answers

What directly influences the properties of transition elements?

The surrounding ligands and environment Signup and view all the answers

Which characteristic is NOT typically associated with transition metals?

Strong ionic bonding Signup and view all the answers

How does the electronic configuration of transition metals contribute to their catalytic properties?

Partly filled d orbitals allow for variable oxidation states. Signup and view all the answers

Which element is considered a non-transition element based on its electron configuration?

Zinc (Z = 30) Signup and view all the answers

Which of these pairs of elements both qualify as transition metals?

Iron and Copper Signup and view all the answers

What factor reduces the shielding effect among d electrons?

The shape and orientation of d-orbitals Signup and view all the answers

Which ionization enthalpy trend deviates for Mn2+ and Fe3+ ions?

Trend of increasing second ionization enthalpy Signup and view all the answers

How does exchange energy affect ionization enthalpy?

Loss of exchange energy increases stability, raising ionization enthalpy Signup and view all the answers

What is the relationship between the configuration of Mn+ and Cr+ regarding ionization enthalpy?

Cr+ has a higher ionization enthalpy than Mn+ Signup and view all the answers

What stabilizes the electronic configuration in a d electron system?

The maximization of pairs of opposite spins in degenerate orbitals Signup and view all the answers

How does the d6 configuration relate to ionization enthalpy?

It experiences no loss of exchange energy Signup and view all the answers

What electronic configuration characterizes Fe2+?

d6 Signup and view all the answers

Which statement regarding the ionization enthalpy of Mn2+ is correct?

It is lower than that of Fe2+ Signup and view all the answers

What is a primary reason why transition metals can form a large number of complex compounds?

They have comparatively small metal ion sizes. Signup and view all the answers

Which of the following best describes the catalytic properties of transition metals?

They can adopt multiple oxidation states and form complexes. Signup and view all the answers

In the reaction catalyzed by iron(III), what is the transformation occurring?

Iodide is oxidized and persulphate is reduced to sulfate ions. Signup and view all the answers

What role do the 3d and 4s electrons of transition metals play in catalytic processes?

They facilitate bond formation between reactants and the catalyst surface. Signup and view all the answers

What are interstitial compounds and how are they formed?

Compounds formed when small atoms are trapped in the crystal lattices of metals. Signup and view all the answers

How does the presence of transition metal ions affect activation energy in chemical reactions?

They lower the activation energy by weakening bonds in reacting molecules. Signup and view all the answers

What is one of the outcomes of using finely divided iron in the Haber process?

It catalyzes the reaction leading to ammonia synthesis. Signup and view all the answers

Why does vanadium(V) oxide play a significant role in catalytic processes?

It can stabilize reactants through bond formation at lower activation energy. Signup and view all the answers

What is the melting point of samarium compared to other lanthanoids?

1623 K Signup and view all the answers

Which lanthanoid ions are known to show no color in solid or aqueous state?

Lutetium and Lanthanum Signup and view all the answers

What is the approximate first ionisation enthalpy of lanthanoids?

Around 600 kJ mol Signup and view all the answers

How do the chemical behaviors of earlier members of the lanthanoid series compare to calcium?

Similar reactivity Signup and view all the answers

What causes the coloration in many trivalent lanthanoid ions?

Presence of f electrons Signup and view all the answers

Which ionization enthalpy is notably low for lanthanum, gadolinium, and lutetium?

Third ionization enthalpy Signup and view all the answers

Why do absorption bands of lanthanoid ions appear narrow?

Excitations within f levels Signup and view all the answers

What general trend is noted in the density and properties of lanthanoids?

They change smoothly except for specific elements. Signup and view all the answers

Study Notes

d Orbitals and Transition Elements

d orbitals of transition elements extend more towards the periphery of an atom than s and p orbitals, allowing them to significantly interact with their surroundings.
Ions with a d configuration (n = 1 – 9) often display comparable magnetic and electronic properties.
Partially filled d orbitals lead to unique characteristics, including multiple oxidation states, formation of colored ions, and the ability to create complexes with various ligands.
Transition metals are recognized for their catalytic properties and paramagnetic behavior.
Properties of transition metals show more similarities across a horizontal row compared to non-transition elements.

Transition Element Qualification

Scandium (Z = 21) is classified as a transition element due to its ground state having an incompletely filled 3d orbital (3d¹).
Zinc (Z = 30) is not a transition element since its 3d orbitals are completely filled in both the ground and oxidized states.

Ionization Energies and Trends

Ionization energies rise slightly across the 3d series; higher-charged ions (d configurations without 4s electrons) reflect greater effective nuclear charge.
A predictable increase in second ionization enthalpy may be interrupted at Mn²⁺ and Fe³⁺ due to their d⁵ configurations.
Ionization enthalpy variations are influenced by electron-nucleus attraction, electron-electron repulsion, and exchange energy due to degeneracy in orbitals.

Exchange Energy and Stability

Exchange energy correlates with the number of possible parallel spin pairs in degenerate orbitals, favoring configurations based on Hund’s rule.
Increased stability from exchange energy loss makes ionization more challenging; no loss occurs at d⁶ configurations.
For example, Mn⁺ has a 3d⁵4s¹ configuration, resulting in lower ionization enthalpy compared to Cr⁺ (d⁵).

Complex Compound Formation

Transition metals readily form numerous complex compounds due to their small ionic sizes, high charges, and availability of d orbitals.
Notable examples of complex compounds include [Fe(CN)₆]²⁺ and [Cu(NH₃)₄].

Catalytic Properties

Transition metals and their compounds act as catalysts due to their ability to adopt various oxidation states and form complexes.
Examples include vanadium(V) oxide in the contact process and finely divided iron in the Haber process.
Catalysis involves bonds formation between reactants and catalyst surfaces, enhancing reactant concentration while lowering activation energy.

Interstitial Compounds

Formed when small atoms (H, C, N) fit into metal crystal lattices.
Reaction kinetics, alongside redox potential, is critical in understanding slow reactions, like H₂O oxidation by permanganate.

Oxidizing Reactions of KMnO₄

KMnO₄ reacts with various substances under acidic conditions, yielding distinct products:
- Iodine liberation from KI.
- Conversion of Fe²⁺ (green) to Fe³⁺ (yellow).
- Oxidation of oxalate ions to CO₂.
- Oxidation of hydrogen sulfide to sulfur.
- Oxidation of sulfite to sulfate.
- Oxidation of nitrite to nitrate.

Characteristics of Lanthanoids

Hardness increases with atomic number; samarium is notably hard.
Melting points range from 1000 K to 1623 K for samarium.
Lanthanoid ions exhibit color due to f-electron presence, except for La and Lu.
First ionization enthalpy averages around 600 kJ mol⁻¹, with second ionization about 1200 kJ mol⁻¹.
Chemical reactivity trends from calcium-like behavior in early members to aluminum-like traits in heavier members.

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Description

Explore the unique properties of d orbitals in transition elements. This quiz delves into how these orbitals influence magnetic and electronic properties in atoms and ions. Test your knowledge on how d orbitals compare to s and p orbitals in terms of their interactions with the surrounding environment.