Question

PbI2 sodid but PbI4 liquid why

Answer 1

Answer:

Explanation:

This of solid, liquid, and gas phases as the energy/heat (say rotational energy) of a molecule.

In the macro world, if you have a perfectly round ball, it rolls (of falls in gravity with air pressure) easily (the gas phase - hence, we can apply the Ideal Gas Law as a round ball will all act the same just like the big ball vs small ball DaVinci experiment that they fall at exactly the same rate).

If you have a few bumps, it can sort of stop and start (translating energy into getting over the bump), you get an uneven relation (it hold momentum, but the path (shape) changes - hence that is comparable to the liquid phase). Finally, if it is the worst spiny box, it will not roll at all (the solid phase).

Therefore, the solid versus liquid is calculating if the outer electron repulsion zones ‘roundness’. PbCl2 has two huge ‘spines’ of Chlorine which bump things and stop spinning, so it melts and boils at higher temperature; it is a solid phase.

However, PbCl4 has four spines of Cl sticking out, which makes the spines sort of like maybe two bumps that can ‘roll’ versus ‘brake’. So, that has medium melting and boiling points, so a ‘liquid phase’ At the same temperature the 4 is not a ‘spiny’ and more ‘humpy’ so the phases can be different at room temperature.