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Assertion : In transition elements radii...

Assertion : In transition elements radii of 5d series are virtually the same as those of the corresponding members of 4d series.
Reason : The filling of 4f orbitals before 5d orbitals results in regular decrease in atomic radii.

A

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

B

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

C

If assertion is trun but reason is false.

D

If both assertion and reason are false.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the question, we need to analyze the assertion and the reason provided, and determine their validity. ### Step-by-Step Solution: 1. **Understanding the Assertion**: - The assertion states that the radii of the 5d series transition elements are virtually the same as those of the corresponding members of the 4d series. - This is indeed true. The atomic radii of 4d and 5d transition metals are similar due to the effects of lanthanide contraction. 2. **Understanding the Reason**: - The reason given is that the filling of 4f orbitals before the 5d orbitals results in a regular decrease in atomic radii. - This is also true. The filling of the 4f orbitals leads to poor shielding of the nuclear charge, which causes an increase in effective nuclear charge felt by the outer electrons. 3. **Connection Between Assertion and Reason**: - The reason explains why the radii of 5d elements are similar to those of 4d elements. The poor shielding effect of the 4f electrons causes the atomic radius to decrease, which compensates for the increase in radius expected from the increase in principal quantum number (n) when moving from 4d to 5d. 4. **Conclusion**: - Both the assertion and the reason are correct, and the reason correctly explains the assertion. ### Final Answer: Both the assertion and the reason are correct, and the reason supports the assertion.
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How would you account for the following : (i) The metallic radii of the third (5d) series of transition metals are virtually the same as those of the corresponding group members of the seconds (4d) series. (ii) There is a greater range of oxidation states among the actinoids than among the lanthanoids.

How would you account for the following? (i)The atomic radii of the metals of the third (5d) series of transition elements are virtually the same as those of the corresponding members of the second (4d) series. (ii)The E^(@) value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) couple or Fe^(3+)//Fe^(2+) couple. (iii)The highest oxidation state of a metal is exhibited in its oxide or fluoride.

Which of the following be the basis of entry of an electron is 4s orbital before 3d orbital ?

Why is 4s orbital filled before the filling of 3d orbital?

Assertion (A) : When the transition element ionises, the 4s -orbital electrons are removed before the 3d -orbital electrons. Reason (R ) : The energy of 3d -orbital electrons is lower than that of 4s -orbital electrons.

Assertion : 4d and 5d series elements have nearly same atomic radius. Reason : Lanthanoid contraction.

The transition element iron belongs to ul"4d-series of transition elements."

How would you account for the following ? (i) Many of the transition elements are known to form interstitial compounds. (ii) The metallic radii of the third (5d) series of transition metals are virtually the same as those of the correponding group members of the second (4d) series.

First IE of 5d seties element are higher than those of 3d and 4d series elements. This is due to:

Assertion (A) : The atomic radii of the electrons of oxygen family are smaller than the atomic radii of corresponding electrons of the nitrogen family Reason (R ) : The members of oxygen family are all more electronegative and thus have lower value of nuclear than those of the nitrogen family