Which of the following factors may be regarded as the main cause of lanthanide contraction?(AIEEE 2005)a)Greater shielding of 5d electron by 4f electronsb)Poorer shielding of 5d electron by 4f electronsc)Effective shielding of one of 4f electron by another in the subshelld)Poor shielding of one of 4felectron by another in the subshellCorrect answer is option 'D'. Can you explain this answer?

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Which of the following factors may be regarded as the main cause of lanthanide contraction?

(AIEEE 2005)

a)
Greater shielding of 5d electron by 4f electrons
b)
Poorer shielding of 5d electron by 4f electrons
c)
Effective shielding of one of 4f electron by another in the subshell
d)
Poor shielding of one of 4f electron by another in the subshell

Correct answer is option 'D'. Can you explain this answer?

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Which of the following factors may be regarded as the main cause of la...

Lanthanide contraction is due to poor shielding of one of 4f electron by another in the subshell.

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Explanation:

The main cause of lanthanide contraction is the poor shielding of one 4f electron by another in the subshell.

The lanthanide series consists of elements with atomic numbers from 57 to 71, and they are characterized by the filling of the 4f subshell. As we move from left to right across the lanthanide series, there is an increase in the nuclear charge due to the addition of protons in the nucleus. This increase in nuclear charge results in a stronger attraction between the nucleus and the outermost electrons.

The lanthanide contraction refers to the decrease in atomic and ionic radii of the elements in the lanthanide series as we move from left to right. This decrease in size is primarily due to the poor shielding of one 4f electron by another in the subshell.

Shielding refers to the ability of inner electrons to reduce the effective nuclear charge felt by the outermost electrons. In the case of lanthanides, the 4f subshell is shielded by the 5s, 5p, and 5d subshells. However, the 4f electrons themselves do not shield each other effectively.

The 4f electrons are relatively ineffective at shielding each other because they are quite diffuse and have poor overlap with each other. As a result, the 4f electrons experience a relatively high effective nuclear charge from the nucleus, leading to a strong attraction and contraction of the electron cloud.

This poor shielding of one 4f electron by another in the subshell results in a higher effective nuclear charge experienced by the outermost electrons. As a result, the atomic and ionic radii of the lanthanide elements decrease as we move from left to right across the series.

Therefore, option D, which states that the poor shielding of one 4f electron by another in the subshell is the main cause of lanthanide contraction, is the correct answer.

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Which of the following factors may be regarded as the main cause of lanthanide contraction?(AIEEE 2005)a)Greater shielding of 5d electron by 4f electronsb)Poorer shielding of 5d electron by 4f electronsc)Effective shielding of one of 4f electron by another in the subshelld)Poor shielding of one of 4felectron by another in the subshellCorrect answer is option 'D'. Can you explain this answer?

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Which of the following factors may be regarded as the main cause of lanthanide contraction?(AIEEE 2005)a)Greater shielding of 5d electron by 4f electronsb)Poorer shielding of 5d electron by 4f electronsc)Effective shielding of one of 4f electron by another in the subshelld)Poor shielding of one of 4felectron by another in the subshellCorrect answer is option 'D'. 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 factors may be regarded as the main cause of lanthanide contraction?(AIEEE 2005)a)Greater shielding of 5d electron by 4f electronsb)Poorer shielding of 5d electron by 4f electronsc)Effective shielding of one of 4f electron by another in the subshelld)Poor shielding of one of 4felectron by another in the subshellCorrect answer is option 'D'. 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 factors may be regarded as the main cause of lanthanide contraction?(AIEEE 2005)a)Greater shielding of 5d electron by 4f electronsb)Poorer shielding of 5d electron by 4f electronsc)Effective shielding of one of 4f electron by another in the subshelld)Poor shielding of one of 4felectron by another in the subshellCorrect answer is option 'D'. Can you explain this answer?.

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