Which characteristic is not a periodic trend? * O atomic radius
O electron affinity
O ionization energies
O number of elements in a group

The question is incomplete. complete question is attached belowanswer: correct answer is option b  i.e.  solid particles  reason: filter paper has small pores, through which smaller particles can pass through. however, solid particles  have relatively larger size. hence, they are least likely to pass through.

Ithink chemical bonding

Its not chemical its not radiation and its not convection because there is not movement of fluids so it is thermal conduction