Identify the similarity in the atoms of pairs of elements given below:

(i) Na (atomic number=11) and


K (atomic number=19)


(ii) B (atomic number=5) and


C (atomic number=6)

(i) Both Na and K belongs to the same group (group I). Both contains same number of electrons in their valence shells i.e. 1

(ii) Both B and C belong to the same period (2nd period). Both contains same number of shells i.e. 2


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