Question

is there any reason behind the three columns of group 8B?

Answer 1

@caozeyuan
Group 8 is a group of chemical element in the periodic table. It consists of iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs). They are all transition metals. Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior.

Fe
Iron
55.845

Ru
Ruthenium
101.07

Os
Osmium
190.23

Hs
Hassium
270

Answer 2

I wanted to say something but I found this article on wikipedia that sums it up, https://en.wikipedia.org/wiki/Group_(periodic_table)
Turns out the iron, cobalt and nickel group were considered the group VIII before IUPAC and CAS, I guess, decided they weren't a single group.