why argon is considered as a non polar molecular solid?
Argon does not possess any type of charge due to neighbour atom therefore has zero polarity. Thus argon is considered as non-polar molecular solid. The argon atoms are held by weak dispersion forces or London forces.
Usually, these non-polar molecular solids are soft and non-conductors of electricity. They have low melting points and are usually in liquid or gaseous state at room temperature and pressure.