Answer:
Transition metals and lanthanide metals
Explanation:
Alkali metals, alkaline earth metals, halogens, and noble gases are all part of the main group elements.
Periods and families simply refer to the rows and columns of the periodic table. They don't specify the type of element.
Dmitri Mendeleev was the first to publish the classification.
Answer:
energy
Explanation:
The amount of energy carried by a wave is related to the amplitude in waves.
