Name: Lanthanoids
Uploaded: 2019-07-19
Duration: 8 min 37 s
Description: This video tells us about the lanthanide elements, their discoveries, atomic numbers, properties, etc. Let's explore the video to know more about them.

Question

What is the effect of lanthanoid contraction on the chemistry of the lanthanoids?

Accepted Answer

In the lanthanoid series, the atomic or ionic radii of the elements decrease with the increase in the atomic number of the elements due to the less shielding effect of $4 f$ electrons. This phenomenon is called the lanthanoid contraction.

The effects of the lanthanoid contraction on the chemistry of the lanthanoids are followings:

(i) Due to the lanthanoid contraction, the basicity of their trihydroxides decreases with the increase in the atomic number of the elements.

(ii) Due to the lanthanoid contraction, all lanthanoids exhibit similar size therefore, the properties of the lanthanoids are quite similar, so the separation of the lanthanoids is a difficult process.

(iii) Due to the lanthanoid contraction, the elements of the first and the second transition series resemble each other much more than the elements of the first and the second transition series.

(iv) The common oxidation state of the lanthanoids is $+ 3$ .

${E^{\circ}}_{(V)}$	$Ti$	$V$	$Cr$	$Mn$	$Fe$	$Co$
$M^{3 +} M^{2 +}$	$- 0.37$	$- 0.26$	$- 0.41$	$+ 1.57$	$+ 0.77$	$+ 1.97$

What is the effect of lanthanoid contraction on the chemistry of the lanthanoids?

Important Questions on d-and f-Block Elements

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