CUET Preparation Today
Case: Read the passage and answer the following questions The f-block consists of the two series, lanthanoids (the fourteen elements following lanthanum) and actinoids (the fourteen elements following actinium). Because lanthanum closely resembles the lanthanoids, it is usually included in any discussion of the lanthanoids for which the general symbol Ln is often used. They have only one stable oxidation state and their chemistry provides an excellent opportunity to examine the effect of small changes in size and nuclear charge along a series of otherwise similar elements. |
| What happens to the atomic size of the lanthanides with an increase in atomic number? |
Radius decreases Radius increases First increase then decrease Remains the same |
| Radius decreases |
| Due to lanthanoid contraction the size of the atoms of the lanthanoid series decrease with the increase of atomic number. |
