Which element is most abundant in the Earth’s atmosphere?
(10 Points)
A. Oxygen
B. Carbon
C. Hydrogen
D. Nitrogen

Compare and contrast physical changes with chemical changes.

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.

Does the number of ions in solution increase, decrease, or remain constant? it continuously decreases. it continuously increases. it decreases at first, then increases. it increases at first, then decreases.