The halogens that are gases at standard temperature and pressure (STP) are:

* Fluorine (F₂)

* Chlorine (Cl₂)

Here's why:

* Fluorine (F₂) and Chlorine (Cl₂) have relatively weak intermolecular forces due to their smaller size and lower molecular mass. These forces are easily overcome at room temperature and pressure, resulting in their gaseous state.

The other halogens, bromine (Br₂) and iodine (I₂), are liquids and solids at STP, respectively, due to stronger intermolecular forces.