PH3
Also known as phosphine
Answer: dispersion forces, dipole-dipole and hydrogen bonds
Explanation:
It changes because when the 2 tectonic plates collide they form mountains and volcanoes.
Continental drift causes tectonic plates to either "pull apart" or "crash" into each other.
Plates that crash into each other either form mountains, or when one slides under the other (a subduction zone) volcanoes from.
The difference between short period and long period is based upon the number of elements in each period. Shortest period is the first period which contains elements, while the longest period is the 6th period which contains 32 elements.