Write the reason for the following (number in parenthesis is atomic number of the substance)

(i) Lithium (3) and sodium (11) are considered as active metals.


(ii) Fluorine (9) is more reactive than chlorine (17).

(i) Lithium and sodium contain only single electrons in their valence electrons which they can readily loose to react. Due to their high reactivity with water, they are considered as active metals.

(ii) Fluorine lies above chlorine in the 17th group. This indicates that fluorine has much higher electronegativity than chlorine due to which it tends to gain electron more easily. That’s why fluorine is more reactive than chlorine.


17