Ключевые слова: actinides, alkali, atomic, chemical, chemistry, compounds, configuration, dive, earth, electron, element, elements, essential, explore, gases, groups, guide, halogens, handbook, key, lanthanides, mass, metalloids, metals, molar, navigate, noble, nonmetals, overview, periodic, periods, properties, reference, science, secrets, structure, table, transition, trends, unlocking,