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Class 12 Exam  >  Class 12 Questions  >  Which of the following statements is not corr... Start Learning for Free
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Which of the following statements is not correct?    
  • a)
    La(OH)3, is less basic than Lu(OH)3
  • b)
    In lanthanoid series, ionic radius of Ln3+ ions decreases
  • c)
    La is actually an element of transition series rather than lanthanoid series
  • d)
    Atomic radii of Zr and Hf are same because of lanthanoid contraction
Correct answer is option 'A'. Can you explain this answer?
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Verified Answer
Which of the following statements is not correct? a)La(OH)3, is less b...
La(OH)3 is more    basic than Lu(OH)3 beacuse La3+ ion is larger than Lu3+ ion
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Most Upvoted Answer
Which of the following statements is not correct? a)La(OH)3, is less b...
Explanation:

The correct answer is option A. La(OH)3 is less basic than Lu(OH)3. Let's analyze each statement to understand why.

a) La(OH)3 is less basic than Lu(OH)3:

- The basicity of a compound is determined by the availability of hydroxide ions (OH-) in the compound.
- Lanthanides are a series of elements that have similar chemical properties due to their similar electronic configurations.
- As we move across the lanthanide series from La to Lu, the ionic radius of the Ln3+ ions decreases gradually.
- The decrease in ionic radius results in stronger electrostatic attraction between the Ln3+ ions and the hydroxide ions in the compound.
- Therefore, as we move from La(OH)3 to Lu(OH)3, the basicity of the compounds increases because the hydroxide ions are more tightly held by the smaller Ln3+ ions.
- Hence, the statement that La(OH)3 is less basic than Lu(OH)3 is incorrect.

b) In the lanthanoid series, the ionic radius of Ln3+ ions decreases:

- This statement is correct. As we move from La to Lu in the lanthanoid series, the ionic radius of the Ln3+ ions decreases gradually.
- This trend is known as the "lanthanoid contraction," which occurs due to poor shielding of the outer electrons by the f-orbitals.
- The decrease in ionic radius has various effects on the chemical and physical properties of the lanthanide elements.

c) La is actually an element of the transition series rather than the lanthanoid series:

- This statement is incorrect. La (Lanthanum) is considered the first element of the lanthanoid series.
- Lanthanum has atomic number 57 and belongs to Period 6 of the periodic table.
- It has a similar electronic configuration to the other lanthanides, with the 4f orbital being progressively filled.
- Therefore, La is considered a part of the lanthanoid series.

d) Atomic radii of Zr and Hf are the same because of the lanthanoid contraction:

- This statement is correct. Zirconium (Zr) and Hafnium (Hf) are elements that belong to the transition metal series.
- Zr has atomic number 40, and Hf has atomic number 72.
- Due to the lanthanoid contraction, the ionic radii of the lanthanides and the transition metals following them are very similar.
- Therefore, Zr and Hf have similar atomic radii, and this similarity is attributed to the lanthanoid contraction.

To summarize, the correct answer is option A because La(OH)3 is actually more basic than Lu(OH)3. The other statements are correct.
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Read the passage given below and answer the following questions: In transition elements, generally, ions of the same charge in a given series show progressive decrease in radius with increasing atomic number. This is because the new electron enters a d orbital each time the nuclear charge increases by unity. But the radii of the third (5 d) series are virtually the same as those of the corresponding members of the second series. This phenomenon is associated with the intervention of the 4f orbitals which must be filled before the 5d series of elements begin. The filling of 4f before 5d orbital results in a regular decrease in atomic radii called Lanthanoid contraction. In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.Following are the transition metal ions of 3d series: Ti4+, V2+, Mn3+, Cr3+ (Atomic number: Ti = 22, V = 23, Mn = 25, Cr = 24)Assertion (

Read the passage given below and answer the following questions: In transition elements, generally, ions of the same charge in a given series show progressive decrease in radius with increasing atomic number. This is because the new electron enters a d orbital each time the nuclear charge increases by unity. But the radii of the third (5 d) series are virtually the same as those of the corresponding members of the second series. This phenomenon is associated with the intervention of the 4f orbitals which must be filled before the 5d series of elements begin. The filling of 4f before 5d orbital results in a regular decrease in atomic radii called Lanthanoid contraction. In these questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.Following are the transition metal ions of 3d series: Ti4+, V2+, Mn3+, Cr3+ (Atomic number: Ti = 22, V = 23, Mn = 25, Cr = 24)Assertion (

Which of the following statements is not correct? a)La(OH)3, is less basic than Lu(OH)3b)In lanthanoid series, ionic radius of Ln3+ ions decreasesc)La is actually an element of transition series rather than lanthanoid seriesd)Atomic radii of Zr and Hf are same because of lanthanoid contractionCorrect answer is option 'A'. Can you explain this answer?
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Which of the following statements is not correct? a)La(OH)3, is less basic than Lu(OH)3b)In lanthanoid series, ionic radius of Ln3+ ions decreasesc)La is actually an element of transition series rather than lanthanoid seriesd)Atomic radii of Zr and Hf are same because of lanthanoid contractionCorrect answer is option 'A'. Can you explain this answer? for Class 12 2024 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about Which of the following statements is not correct? a)La(OH)3, is less basic than Lu(OH)3b)In lanthanoid series, ionic radius of Ln3+ ions decreasesc)La is actually an element of transition series rather than lanthanoid seriesd)Atomic radii of Zr and Hf are same because of lanthanoid contractionCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for Class 12 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following statements is not correct? a)La(OH)3, is less basic than Lu(OH)3b)In lanthanoid series, ionic radius of Ln3+ ions decreasesc)La is actually an element of transition series rather than lanthanoid seriesd)Atomic radii of Zr and Hf are same because of lanthanoid contractionCorrect answer is option 'A'. Can you explain this answer?.
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