Answer:
John Dalton
Explanation:
Both John Dalton and Democritus thought that the atom was an indivisible sphere until J.J. Thompson came out with the plum pudding model. Hope I helped!
Answer:
The group 18 elements are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). These elements are non-reactive and are called noble gases as they have their outermost orbit complete. Due to stable electronic configuration they hardly react with other elements.The name comes from the fact that these elements are virtually unreactive towards other elements or compounds.The group 18 elements are called noble or inert gases. As the name suggests these are inert because chemically they are very less reactive or not at all reactive.The full valence electron shells of these atoms make the noble gases extremely stable.
Answer:
A change in form or appearance of matter
Explanation:
