• # question_answer 102)   Write down the outermost electronic configuration of alkali metals. How will you justify their placement in group I of the periodic table?

The electronic configuration of outermost orbit in the alkali metals is $n{{s}^{1}}$ where n = 2, 3, 4, 5, 6 and 7. Li ;         Na ;          K ;      Rb ;     Cs ;          Fr $2{{s}^{1}}$       $3{{s}^{1}}$        $4{{s}^{1}}$      $5{{s}^{1}}$     $6{{s}^{1}}$         $7{{s}^{1}}$ Because of their similarity in electronic configuration [noble gas] $n{{s}^{1}}$, they are placed in the same group, i.e., IA of the periodic table. These elements are monovalent and closely resemble in their physical and chemical properties.