Which best describes a spontaneous process as it relates to the second law of thermodynamics?

it destroys heat.

it requires work.

it creates energy.

it occurs naturally.

Having in mind that a spontaneous process is capable of proceeding in a given direction without needing to be driven by an outside source of energy, then it must occur naturaly. This is actually spontaneous. Also take into account that in order to define a spontaneous pattern we need to state  no work performed on the system or on the surroundings.

Ifound this on google “these two compounds have a different ionic structure. caesium ion is larger in size when compared to the sodium ion. the charge gets more area to spread out evenly. so caesium chloride has a lower melting point than sodium chloride.” i hope this you for what your looking for