Consider the compounds Cl2, HCl, F2, NaF, and HF. Which compound has a boiling point closest to that of argon? Explain how you came up with your answer.

Cl2, Chlorine molecule has a boiling point closest to that of argon.

This is because Chlorine is made up of discrete and simple molecules making up a simple molecular structure. The molecules associate through weak van der waal's forces of attraction hence low boiling point.

HCl has strong hydrogen bonds.

F2 is very small hence strong forces of attraction.

HF has strong hydrogen bonds

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.