List the following molecules in order of increasing boiling point: Br₂, Cl₂, F₂, 12?
1) Br₂, F₂, Cl₂, 12
2) F₂, Cl₂, Br₂, 12
3) Cl₂, Br₂, F₂, 12
4) Br₂, Cl₂, F₂, 12