The atomic radii of the first group elements are given below :
Group-I element Atomic Radii (pm)
Na 86
K
231
Rb 244
Cs 282
State the reason behind the observed trend in the above elements.

Academic Chemistry NCERT Class 10

Atomic radii increase from Na to Cs due to the addition of new shells as we move down in the group. As new shells are added, hence the effective size of an atom increases.

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Updated on: 10-Oct-2022

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