Chemistry Unit on d- and f- Block Elements

Questions and Answers

What represents the d-block elements in the periodic table?

Groups 3-12 (correct)

Groups 1-2

Groups 13-18

Groups 4-10

Which of the following elements is classified as a transition metal?

Barium

Neon

Iron (correct)

Lithium

What are the two series of inner transition metals called?

Lanthanoids and Actinoids (correct)

Noble Gases and Halogens

Metalloids and Nonmetals

Transition Metals and Alkali Metals

Which oxidation state is commonly stable among transition metals?

+2 Signup and view all the answers

Which of the following compounds contains chromium and is often used in laboratories?

K2Cr2O7 Signup and view all the answers

What type of energy sources do the inner transition elements, Th, Pa, and U, represent?

Nuclear energy Signup and view all the answers

Which orbital is progressively filled in the f-block elements?

4f and 5f Signup and view all the answers

What is the significance of electrode potential values in d- and f-block elements?

They relate to the stability of oxidation states. Signup and view all the answers

What is the enthalpy of atomisation for zinc?

126 kJ mol$^{-1}$ Signup and view all the answers

Which statement is true regarding the ionisation enthalpy of transition elements?

There is a gradual increase in ionisation enthalpy from Scandium to Zinc. Signup and view all the answers

Why do 3d electrons effectively shield 4s electrons from increasing nuclear charge?

They are added to the inner subshell orbital. Signup and view all the answers

What is the trend in atomic radii as we move from Scandium to Zinc?

Atomic radii decrease less rapidly. Signup and view all the answers

What is a notable characteristic of the first ionisation enthalpy of the 3d series metals?

The trend is more erratic compared to non-transition metals. Signup and view all the answers

What is the primary reason for the irregular trend in first ionisation enthalpy among 3d series metals?

Changes in electron shielding effects. Signup and view all the answers

Which transition element has the highest first ionisation enthalpy in the 3d series?

Copper Signup and view all the answers

What is true about the ionisation enthalpies of the first three elements in the transition series?

The difference in their values is small. Signup and view all the answers

What is formed when manganese (II) ions are oxidised by peroxodisulphate?

Permanganate Signup and view all the answers

Which of the following statements about potassium permanganate is true?

It decomposes at 513 K. Signup and view all the answers

Why is the manganate ion considered paramagnetic?

It has one unpaired electron. Signup and view all the answers

Which of the following is a property of permanganate ion?

It is diamagnetic. Signup and view all the answers

What does acidified permanganate solution oxidise iron(II) ions to?

Iron(III) ions Signup and view all the answers

What happens to starch when it reacts with permanganate in an acidified solution?

It reduces permanganate to manganese dioxide. Signup and view all the answers

How are manganate and permanganate ions geometrically characterized?

Tetrahedral Signup and view all the answers

Which of the following reactions involves permanganate as an oxidizing agent?

Oxalate to carbon dioxide Signup and view all the answers

Which transition metal has the highest third ionisation enthalpy based on the content?

Copper (Cu) Signup and view all the answers

What does the term 'dominant term' refer to in the context of ionisation enthalpies?

The second ionisation enthalpy Signup and view all the answers

Which oxidation state is identified as the lowest common oxidation state for transition metals mentioned?

+2 Signup and view all the answers

Why does Zinc (Zn) have a correspondingly low ionisation enthalpy?

The removal of a 4s electron forms a stable d configuration. Signup and view all the answers

Which transition metals have third ionisation enthalpies indicating difficulty obtaining higher oxidation states?

Copper and Nickel Signup and view all the answers

What characteristic do nearly all transition elements exhibit?

High tensile strength Signup and view all the answers

What does the trend in third ionisation enthalpies reflect?

The greater difficulty of removing an electron from d configurations. Signup and view all the answers

What complexity affects the prediction of oxidation states from ionisation enthalpies?

The inability to generalise the effects of d and s electrons. Signup and view all the answers

Which of the following elements does not exhibit typical metallic structures at normal temperatures?

Zinc (Zn) Signup and view all the answers

What is a notable feature of transition metals regarding oxidation states?

They commonly show a variety of oxidation states. Signup and view all the answers

Which lattice structures are observed for Chromium (Cr)?

bcc and hcp Signup and view all the answers

What is the typical characteristic of transition metals in terms of conductivity?

High thermal and electrical conductivity Signup and view all the answers

Which of the following transition metals displays a hexagonal close packed (hcp) structure?

Zirconium (Zr) Signup and view all the answers

Which of the following elements has a body-centered cubic (bcc) structure among the listed?

Tungsten (W) Signup and view all the answers

Which transition element is known to be an exception in exhibiting typical metallic properties?

Mercury (Hg) Signup and view all the answers

What does 'ccp' stand for in the context of lattice structures?

Cubic Close Packed Signup and view all the answers

Study Notes

Overview of d- and f-Block Elements

d-block elements (transition metals) are located in groups 3-12 of the periodic table.
f-block elements (inner transition metals) consist of lanthanides and actinides, found at the bottom of the periodic table.
Key transition elements include iron (Fe), copper (Cu), silver (Ag), and gold (Au), pivotal in human civilization.
Lanthanides (4f) span from cerium (Ce) to lutetium (Lu), while actinides (5f) range from thorium (Th) to lawrencium (Lr).

Properties of Transition Elements

Transition metals exhibit typical metallic characteristics: high tensile strength, ductility, malleability, and good thermal/electrical conductivity.
Exceptions to typical structures include zinc (Zn), cadmium (Cd), mercury (Hg), and manganese (Mn), which do not exhibit standard metallic structures.

Lattice Structures

Various typical metallic lattice structures include:
- Body-Centered Cubic (bcc): Sc, Cr, Mo, and W.
- Face-Centered Cubic (ccp): Ni, Cu, and Ag.
- Hexagonal Close Packed (hcp): Ti, Co, and Ru.

Enthalpy of Atomisation

Transition metals have higher enthalpies of atomisation due to numerous unpaired electrons leading to stronger interatomic interactions.
Zinc has the lowest enthalpy of atomisation in the 3d series, indicating weaker bonding compared to others.

Ionisation Enthalpy Trends

Ionisation enthalpies generally increase across the series due to increasing nuclear charge.
Variations in ionisation enthalpy are less steep than in non-transition elements.
The removal of electrons affects the relative energies of 4s and 3d orbitals, influencing ionisation values.

Oxidation States

Transition metals exhibit a wide range of oxidation states; this diversity is essential for their chemical reactivity.
Common oxidation states for first-row transition metals include +1, +2, +3, +4, +5, and +6.

Compounds and Reactions of Transition Metals

Manganese can exhibit variable oxidation states, such as transitioning from Mn(II) to Mn(VI).
Potassium permanganate (KMnO4) exhibits intense color and is used in various oxidation reactions:
- It oxidises oxalates to carbon dioxide, iron(II) to iron(III), and nitrites to nitrates.

Molecular Structure and Properties

The manganate ion (MnO4^2-) is tetrahedral and paramagnetic due to an unpaired electron, while permanganate (MnO4^-) is diamagnetic with no unpaired electrons.
Potassium permanganate is poorly soluble in water but decomposes upon heating.

Summary of Reactions Involving Permanganate

Acidified permanganate solutions participate in redox reactions:
- Oxidation of oxalate: COO^- → 5 CO2 + 10 e^-
- Oxidation of Fe(II): Fe^2+ → Fe^3+ + e^-
The balancing of reductant half-reactions is crucial for writing complete redox reactions.

These notes encapsulate the fundamental aspects and properties of d- and f-block elements and highlight their significance in chemistry.

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Description

This quiz focuses on the positions and properties of d- and f-block elements in the periodic table. You will test your knowledge about transition metals like iron, copper, silver, and gold. Prepare to explore these essential chemical families in depth.