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?

Answer:

  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.