What is the metallic radius?
Everything is written on the image below:
As you can see, metallic radius is defined as one-half of the distance between the nuclei of two atoms in crystal or between two adjacent metal ions in the metallic lattice.
- decrease across the period due to increase in the effective nuclear charge.
- increase down the group due to increase in principal quantum number.
If you need more than this, you can find here much more: