Advertisements
Advertisements
प्रश्न
Beryllium and magnesium do not give colour to flame whereas other alkaline earth metals do so. Why?
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.
APPEARS IN
संबंधित प्रश्न
Which of the following has the highest hydration energy
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.
In context with beryllium, which one of the following statements is incorrect?
Write a balanced chemical equation for the following chemical reaction.
Rubidium with oxygen gas
Beryllium halides are covalent whereas magnesium halides are ionic why?
Alkaline earth metal (A), belongs to 3rd period reacts with oxygen and nitrogen to form compound (B) and (C) respectively. It undergoes metal displacement reaction with AgNO3 solution to form compound (D). Identify A, B, C and D.
Explain the important common features of Group 2 elements.
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 ______.
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.
Why are BeSO4 and MgSO4 readily soluble in water while CaSO4, SrSO4 and BaSO4 are insoluble?
Assertion (A): Beryllium carbonate is kept in the atmosphere of carbon dioxide.
Reason (R): Beryllium carbonate is unstable and decomposes to give beryllium oxide and carbon dioxide.
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.
Among the following alkaline earth metal halides, one which is covalent and soluble in organic solvents is ______.
Among the following alkaline earth metal halides, one which is covalent and soluble in organic solvents is ______.
MgBr2 and Mgl2 are soluble in acetone because of ______.
