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प्रश्न
Beryllium and magnesium do not give colour to flame whereas other alkaline earth metals do so. Why?
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उत्तर
When an alkaline earth metal is heated, the valence electrons get excited to a higher energy level. When this excited electron comes back to its lower energy level, it radiates energy, which belongs to the visible region. Hence, the colour is observed. In Be and Mg, the electrons are strongly bound. The energy required to excite these electrons is very high. Therefore, when the electron reverts back to its original position, the energy released does not fall in the visible region. Hence, no colour in the flame is seen.
संबंधित प्रश्न
Discuss the general characteristics and gradation in properties of alkaline earth metals.
Which one of the alkaline earth metal carbonates is thermally the most stable?
The product obtained as a result of a reaction of nitrogen with CaC2 is ______.
Assertion: Generally alkali and alkaline earth metals form superoxides.
Reason: There is a single bond between O and O in superoxides.
Assertion: BeSO4 is soluble in water while BaSO4 is not
Reason: Hydration energy decreases down the group from Be to Ba and lattice energy remains almost constant.
Write a balanced chemical equation for the following chemical reaction.
Rubidium with oxygen gas
Discuss briefly the similarities between beryllium and aluminium.
Some of the Group 2 metal halides are covalent and soluble in organic solvents. Among the following metal halides, the one which is soluble in ethanol is ______.
When sodium is dissolved in liquid ammonia, a solution of deep blue colour is obtained. The colour of the solution is due to ______.
Identify the correct formula of halides of alkaline earth metals from the following.
(i) BaCl2.2H2O
(ii) BaCl2.4H2O
(iii) CaCl2.6H2O
(iv) SrCl2.4H2O
Name an element from Group 2 which forms an amphoteric oxide and a water soluble sulphate.
Discuss the trend of the following:
Thermal stability of carbonates of Group 2 elements.
Discuss the trend of the following:
The solubility and the nature of oxides of Group 2 elements.
Why are BeSO4 and MgSO4 readily soluble in water while CaSO4, SrSO4 and BaSO4 are insoluble?
An element of group 2 forms covalent oxide which is amphoteric in nature and dissolves in water to give an amphoteric hydroxide. Identify the element and write chemical reactions of the hydroxide of the element with an alkali and an acid.
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