What are the group trends for atomic radius?

1 Answer
Jul 1, 2018

Across a period: #darr#
Down a period: #uarr#

Explanation:

To be honest, the way I remember this is #color(darkblue)("francium (Fr)")#.

Fr has the #color(darkblue)("largest")# atomic radius. Therefore, as you move farther from francium, the smaller your radius will be. If you move closer to francium, the larger your radius.

https://glossary.periodni.com/glossary.php?en=periodic+table+of+the+elements

You can see Fr in the bottom left-hand corner. Therefore, if you move across any period from left to right, atomic radius will #color(darkblue)("decrease")# because you're moving farther from Fr.

Going down a period will #color(darkblue)("increase")# your atomic radius because you're moving closer to Fr.