The appropriate answer is a. it involves a change in the molecular structure of the substance. A change in phase or state is referred to as a physical change. For example...liquid water freezing is a physical change because the state changes but solid water is still H20. Separating water into its constituent atoms, hydrogen and oxygen is a chemical change because the molecular structure of water is now non existent.
Answer: Cations (positively-charged ions) and anions (negatively-charged ions) are formed when a metal loses electrons, and a nonmetal gains those electrons. The electrostatic attraction between the positives and negatives brings the particles together and creates an ionic compound, such as sodium chloride.
The answer would be B because you can go and find evidence and facts to conduct an investigation on that.
Tin-120 because an atom has to have a neutral charge. If an atom has 50 electrons it must have 50 protons unless it's an ion. Add 70 to the atomic mass because it has 70 neutrons on top of 50 protons. That equals to 120. Tin has an atomic number of 50 (meaning it has 50 protons) and it has roughly an atomic mass of about 118. If the given has 70 neutrons then it's a isotope of tin.