9) Observe the halogens. Fluorine and chlorine are gases, bromine is a liquid, and
iodine is a solid all at room temperature.
Distinguish between these differences in phase.
A) From Fluorine to lodine, the number of electrons increases.
This allows the intermolecular forces to strengthen from
temporary dipole (dispersion) forces to permanent dipoles.
Therefore, iodine is a solid because it has the most electrons.
B) From Fluorine to lodine, the nucleus gets larger. More
neutrons, protons and electrons allow the atoms of these
elements to become more attracted to each other. This is also
the reason that the halogens are diatomic naturally.
) From Fluorine to lodine, the molecular mass increases. With
the increase in mass, there is an increase in protons. This causes
the strength of the intermolecular forces between particles to
increase as well.
D) From Fluorine to lodine, the molecular mass increases. The
electron polarizability increases with the mass increase. In turn,
this strengthens the temporary dipole (dispersion) forces
between particles
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