Question

Write down the outermost electronic configuration of alkali metals. How will you justify their placement in group 1 of the periodic table?

Answer 1

The group 1 elements are called alkali metals which possess outermost electronic configuration as ns1.All the elements that have same outermost electron configuration possess similar properties and are placed in the same group.

Atomic Number	Symbol	Electronic Configuration
3	\[\ce{Li}\]	1s22s1 (or) \[\ce{[He]}\] 2s1
11	\[\ce{Na}\]	1s22s22p63s2 (or) \[\ce{[Ne]}\] 3s1
19	\[\ce{K}\]	1s22s22p63s24s1 (or) \[\ce{[Ar]}\] 4s1
37	\[\ce{Rb}\]	1s22s22p63s23d104s2sp65s1 (or) \[\ce{[Kr]}\] 5s1
55 87	\[\ce{Cs}\] \[\ce{Fr}\]	1s22s22p63s23p63d104s24p65d105s25p66s1 (or) \[\ce{[Xe]}\] 6s1 \[\ce{[Rn]}\] 7s1