What particles of an atom are inside the neuculas?

*It's nucleas. There are protons, neutrons and electrons.

This is what i found on google “according to the collision theory, the following criteria must be met in order for a chemical reaction to occur: molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. molecules must collide with the proper orientation.” i hope this information you.

Gas will most likely  fill the container