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Assertion : Lanthanoids show a limited o...

Assertion : Lanthanoids show a limited of ixidation states wheres actanoids show a large number of oxidation states.
Reason : Energy gap between `4f, 5d` and `6s` subshells is small wheras that between `5f, 6d` and `7s` subshell is large.

A

If both assetion and reason are true and the reason is the correct explanation of the assertion.

B

If both assertion and reason are ture but reason is not the correct explanation of the assertion.

C

If assertion is true but reason is false.

D

If assertion is false but reason is true.

Text Solution

Verified by Experts

The correct Answer is:
C
Reason is false because energy gap between `4f`, `5d` and `6s` is large whereas that between `5f, 6d` and is small.
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STATEMENT-1 : Lanthanoids show less oxidation states than actinoids and STATEMENT-2: 4f subshell is dieperseated than 5f .

Lanthanoids and actinoids are f-block elements in which the last electron enters the anti-penultimate energy level. The most common oxidation state of lanthanoids is +3, though +2 and +4 oxidation states are exhibited by some of the elements. In lanthanoid series, there is a progressive decrease in atomic and ionic radii, known as lanthanoid contraction. Unlike lanthanoids, actinoids show a large number of oxidation states. Name an element of lanthanoid series, which is known to show +4 oxidation state. Is it a strong oxidising agent or reducing agent?

Lanthanoids and actinoids are f-block elements in which the last electron enters the anti-penultimate energy level. The most common oxidation state of lanthanoids is +3, though +2 and +4 oxidation states are exhibited by some of the elements. In lanthanoid series, there is a progressive decrease in atomic and ionic radii, known as lanthanoid contraction. Unlike lanthanoids, actinoids show a large number of oxidation states. Which is the last element of the actinoid series? Write its electronic configuration.

Statement 1 : Energy gap between 4f, 5d and 6s subshells is small whereas that between 5f, 6d and 7s subshells is large. Statement 2 : Langhanoides show a limited number of oxidation state whereas actinoids show a large number of oxiation states.

Lanthanoids and actinoids are f-block elements in which the last electron enters the anti-penultimate energy level. The most common oxidation state of lanthanoids is +3, though +2 and +4 oxidation states are exhibited by some of the elements. In lanthanoid series, there is a progressive decrease in atomic and ionic radii, known as lanthanoid contraction. Unlike lanthanoids, actinoids show a large number of oxidation states. Name two lanthanoids which exhibit +2 oxidation state.

A2Z-THE D AND F BLOCK ELEMENTS-Section B - Assertion Reasoning
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