What do elements in the same column of the Periodic Table usually have in common?

A. same atomic mass

B. same atomic number

C. same number of electron shells

D. same number of electrons in their outer shell

Question

What do elements in the same column of the Periodic Table usually have in common?

A. same atomic mass

B. same atomic number

C. same number of electron shells

D. same number of electrons in their outer shell

anonymous · Answer

D.
The same number of electrons in the outer (or valence) shell.  This also makes it so they have similar chemical properties.