Briefly, but informatively, discuss the four common mode of separation in chromatography.

Can you me with this i really appreciate it

Select all of the statements which are true. electrons are located in shells or orbits around the atom. electrons orbit slowly around the atom. electrons travel in one flat path around the nucleus of an atom. the valence of an atom is determined by the number of electrons in the atom's outermost shell.

What element has similar physical and chemical properties as boron.