Question

Explain Alkali metals have largest covalent radii

Answer 1

Hello Friend !


Alkali metals do have the largest atomic volume in their period. When we compare the data for the atomic radii of elements in a period, we find that alkali metals have the largest atomic radii, because of which their atomic volume will also be the largest. This is because as we proceed from left to right in a period, both number of protons and the number of electrons increase by a factor of one. But since the electrons are added to the same valence shell, the effective nuclear charge is more. Hence the attraction between the nucleus and the outermost shell of electrons increases because of which it is pulled in closer to the nucleus, thereby reducing the size of the atom. This atomic volume increases abruptly on reaching the noble gases due to increase in inter atomic repulsion, but would still be smaller than alkali metals.



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Answer 2

Alkali metals have largest covalent radii because they poses only 1 electron in their outer level and good screening in inner level and that results lower force of attraction.