It has been shown that the lanthanide elements are highly electropositive and form essentially ionic compounds. It is observed for these elements that +3 (i.e. formation of tripositive ions, Ln3+) is the principal or common oxidation state exhibited by all of them. This is said to be the most stable oxidation state of the lanthanides. … Read more
d and f Block Elements Ionic radii A great degree of variation is seen in the atomic radii across each transition series. The atomic radii of the d-block elements within a given series decrease with increase in the atomic number. This is due to the increase in the nuclear charge that attracts the electron cloud … Read more
d and f Block Elements Occurrence and characteristics of transition metals The transition elements have characteristic properties that are associated with all the metals having incomplete d sublevels. They collectively have variable oxidation states which means that they form complex ions with ligands, have coloured compounds, and display catalytic and magnetic properties. The d-block elements … Read more
d and f Block Elements Chemical reactivity and lanthanoid contraction and its consequences The lanthanides have low charge density due to their larger size in spite of having a high charge (+3). Hence, they do not cause much polarization of the ligands and have a weak tendency for complex formation. If lanthanide elements are ignited … Read more
d and f Block Elements Ionization enthalpy The first IE of the transition metals gradually increases as we move across a series. It is higher than those of s-block elements but lower than p-block elements. Consider a transition metal where electrons are initially removed from the 4s sub-level and then the 3d sub-level. between sublevels, … Read more
d and f Block Elements Actinides: Electronic configuration The elements with occupied 5f- orbitals of (n-2)th are known as 5f-block elements, actinides. There are only thirteen elements from Th90 (5f0 6d2 7s2 ) to No102 (5f14 6d0 7s2 ) should be the members of the actinide series. However, all the fifteen elements from Ac89 (5f0 … Read more
d and f Block Elements Comparison with lanthanides Similarities In the atoms of the elements of both the series, three outermost shells are partially filled and remaining inner shells are completely filled but the additional or differentiating electron enters (n-2) f-subshell. The elements of both series exhibit +3 oxidation state which is a prominent and … Read more
d and f Block Elements Catalytic property A catalyst is a substance that alters the rate of a reaction by directing the reaction in an alternative pathway that requires lower activation energy. Catalysts play a crucial role to allow chemical processes to change reaction steps and proceed at an economical rate. The ability of transition … Read more
d and f Block Elements Alloy formation Alloys are homogenous solid solutions of two or more metals obtained by melting and blending the components to produce a hardened solid obtained by cooling the melt. Alloys can be formed using metals with similar atomic radii. The atomic radii should not differ more than 15% so that … Read more
d and f Block Elements Oxidation state The important oxidation states exhibited by actinides are compiled below in the tabular form. Some of them are stable but most of these oxidation states are unstable. It may be seen from these oxidation states that the +2 state is shown by Th and Am only in the … Read more