They are noble (inert) gases. They are nonmetals. They have the same thermal conductivity. They have the same number of protons.
I gave my students this multiple choice question: What do the elements sulfur (S), nitrogen (N), phosphorus (P), and bromine (Br) have in common?

Only one answer is correct among these 4 choices:
- They are noble (inert) gases.
- They are nonmetals.
- They have the same thermal conductivity.
- They have the same number of protons.

Could you tell me which one is correct?

They are nonmetals.