Which of the following statements about ions is NOT CORRECT? A. Anions are negative ions.
B. Anions are formed when an atom loses electrons.
C. Neutral atoms always have the same number of protons as electrons.
D. Cations are positive ions.

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

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.

The fact that the total amount of energy in a system remains constant is a(n)