A chemical reaction is a reaction that changes the molecular structure and is normally irreversible.
Phase transition is when a substance changes from a solid, liquid, or gas state to a different state. Every element and substance can transition from one phase to another at a specific combination of temperature and pressure.
Answer:
The periodic law states “When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties
Either covalent or ionic... they are nonmetals meaning that the are a component in both types of compounds
