Which of the following metals reacts directly with nitrogen to form a nitride?

$A$ chloride salt dissolves appreciably in cold water. When placed on a platinum wire in a Bunsen flame,no distinctive color is noted. Which cation could be present?

Identify the basic oxide from the following.

Lithium shows similarities to magnesium in its chemical behaviour because

Which of the following metallic hydroxides does not dissolve in a solution of sodium hydroxide?

Give brief information on the atomic and ionic radius of alkali metals (Group $I$).