Q52 of 59 Page 35

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

Electronic configuration of group 1 elements is:


1s22s1 =Li


1s22s22p23s1 = Na


1s22s22p23s23p64s1=K


1s2 2s2 2p2 3s2 3p6 3d10 4s2 4p6 5s1=Rb


1s2 2s2 2p2 3s2 3p6 3d10 4s2 4p6 4d10 5s25p66s1=Cs


[Rn] 7s1=Fr


Number of electrons in the valence shell determine the group of an element. All these elements have one electron in their valence shell.


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