[Billy1500]

I just had a general question about the atomic radii trend on the periodic table. Why does the d-block ignore the periodic trend? I look at the d-block on a 3D visual of a periodic table with the radii trend but I can't seem to figure anything out. Does it have something to do with electrons being added to the core and not to the outer shell?

Thanks to anyone who answers.

[AdityaDev]

Have you heard about lanthanide contractions? That's the reason.
The effect results from poor shielding of nuclear charge (nuclear attractive force on electrons) by 4f electrons; the 6s electrons are drawn towards the nucleus, thus resulting in a smaller atomic radius.