Question

Question 40
Identify the elements with the following property and arrange them in increasing order of their reactivity:

(a) An element which is a soft and a reactive metal.

(b) The metal which is an important constituent of limestone.

(c) The metal which exists in liquid state at room temperature.

Answer 1

(a) Potassium (K) and sodium (Na) are soft and reactive (these metals have 1 valence electron that they readily lose to form ${\text{K}}^{+}$ or ${\text{Na}}^{+}$).
(b) Calcium (Ca) is an important constituent of limestone $\left({\text{CaCO}}_3\right)$.
(c) Mercury (Hg) is the only metal which is liquid at room temperature.

Arrangement in increasing order of reactivity: Hg < Ca < Na < K.