Question

Which of the following statements is/are true about s-block elements?

• A. All alkali metals dissolve in liquid ammonia to give deep blue coloured solution
• B. All alkaline earth metals give characteristic color in Bunsen flame
• C. Melting and boiling point of alkali metals decreases from Li to Cs regularly
• D. Alkaline earth metals are relatively softer than alkali metals

Answer 1

Answer: (A), (C)

The correct options are
A All alkali metals dissolve in liquid ammonia to give deep blue coloured solution
C Melting and boiling point of alkali metals decreases from Li to Cs regularly

(a) All alkali metals dissolve in liquid ammonia to give blue coloured solution due to presence of solvated electrons.
(b) Be and Mg do not give characteristic colours in Bunsen flame.
(c) On moving down the group, size of alkali metals increases and the strength of metallic bond decreases which causes a decrease in melting and boiling points.
(d) The alkaline earth metals are relatively harder than the alkali metals. This is due to their smaller size as compared to alkali metals which increases the strength of metallic bond.