Lanthanoid Contraction In the lanthanoid series, with increasing atomic number, the atomic and ionic radii decrease from one element to another but the decrease is very small. Far example : On moving from Ce to Lu, the atomic radii decrease from 183 pm to 173 pm and the decrease is only 10 pm. The ionic radii decrease from 103 pm to 85 pm on moving from Ce3+ to Lu3+ … [Read more...] about Lanthanoid Contraction
Chemistry
Chemical Reactivity, Solubility and Basic Character of Lanthanoids
Chemical Reactivity All the lanthanoids are highly electropositive metals and have almost similar chemical reactivity. This is due to the fact that the lanthanoids differ only in the number of 4f-electrons. Since these electrons are very effectively shielded from interaction with other elements by the overlying 5s, 5p and 6s-electrons, they show very little differences in … [Read more...] about Chemical Reactivity, Solubility and Basic Character of Lanthanoids
Potassium Permanganate
Potassium Permanganate, KMnO4 It is prepared from mineral pyrolusite (MnO2) by following steps : 1) Conversion of Pyrolusite ore to Potassium Manganate The pyrolusite is fused with caustic soda or potassium carbonate in the presence of air or oxidising agent such as potassium nitrate or potassium chlorate to give a green mass due to the formation of potassium manganate. 2 … [Read more...] about Potassium Permanganate
Characteristics of Lanthanoids
f-block elements The elements in which the last electron enters the f-orbital of the atoms are called f-block elements. In these elements, the last electron is added to the third to the outermost (called antepenultimate) energy level i.e. (n-2)f. Their general electronic configuration is (n-2)f1-14 (n-1)d0-1ns2 These elements are also called inner transition … [Read more...] about Characteristics of Lanthanoids
Potassium Dichromate
Potassium Dichromate Properties of Potassium Dichromate 1) Colour and melting point : It is an orange red crystalline solid having melting point of 670 K. 2) Solubility : It is moderately soluble in cold water but readily soluble in hot water. 3) Action of heat : It decomposes on heating to form potassium chromate , chromic acid and oxide. 4 K2Cr2O7 → 4K2CrO4 + 2 … [Read more...] about Potassium Dichromate