Saved Bookmarks
| 1. |
(i) Write the important common features of group 2 elements? (ii) What is meant by retrograde solubility? |
|
Answer» SOLUTION : (i)• Group 2 elements except beryllium are commonly known as alkaline EARTH metals because their oxides and hydroxides are alkaline in nature and these metal oxides are found in the Earth.s crust. • Many alkaline earth metals are used in creating colours and used in fireworks. • Their general electronic configuration is ns? • Atomic and ionic RADII of alkaline earth metals are smaller than alkali metals, on movin down the group, the radii increases. . These elements exhibit +2 oxidation state in their compounds. • Alkaline earth metals have higher ionization enthalpy values than alkali metals and they are less electropositive than alkali metals. • Hydration enthalpies of alkaline earth metals decreases as we go down the group. . Electronegativity values of alkaline earth metals decrease down the group. • Alkaline earth metal salts moistened with concentrated hydrochloric acid gave a characteristic coloured flame, when heated on a platinum wire in a flame. (ii) Gypsum is a SOFT mineral and it is less soluble in water as the temperature increases. This is known as RETROGRADE solubility, which is a distinguishing characteristic of gypsum. |
|