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The s-Block Elements
Beryllium and magnesium do not give colour to flame whereas other alkaline earth metals do so. Why?
Beryllium and magnesium do not give colour to flame because they (Be and Mg) have a small size and very high ionisation enthalpies. The enthalpy of the flame is not sufficient to excite their electrons to higher energy levels. Other alkaline earth metals impart colour to the flame because they have fairly low ionisation enthalpies, so electrons in their atoms can be easily excited by the enthalpy of the flame. The excited electrons on returning to their original positions lose enthalpy in the form of coloured light.
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Why are alkali metals not found in nature?
Lithium shows similarities to magnesium in the chemical behaviour. What is the cause of this similarity?
What is the nature of lithium compounds?
Group 1 elements are called alkali metals. Why?
Why caesium can be used in photoelectric cell while lithium can not be?
In aqueous solution, Li+ ion has lowest mobility. Why?
Lithium has highest ionisation energy in group 1 elements, yet it is strongest reducing agent. Comment.
The softness of group 1 elements increases down the group with increasing atomic number. Give reason.
Which is the most reactive alkali metal and why?
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