The History of the Atomic Model

Discover the fascinating history of the atom! Learn about early ideas and key discoveries.

Early Atomic Models Watch the videos and answer the questions in complete sentences. What did Aristotle think? What did Democritus think? Who were the Alchemists? Can one element be changed into another element? Yes No How many elements exist in nature? 20 92 112 What did Dalton have to say about atoms? What did Thomson discover? Sketch what Thomson thought atoms looked like. What was Thomson's model called? (this is not in the video but you can look it up now!) Chocolate chip cookie model Bowl of soup model Plum pudding model What was the famous experiment Rutherford did? What did Rutherford conclude about the atomic model, based on his experiment? Introduction to Atomic Structure What is the smallest unit of matter? Atom Energy Molecule What particles make up atoms? Label the three (yellow, green, and blue) subatomic particles that make up an atom. electron neutron proton What is an analogy for the relative size of the atom and its particles? Fill in the blanks. The nucleus is held together by the strong nuclear force. What charge does the nucleus of an atom have? positive negative neutral Why does the nucleus have the charge you chose in the previous question? Where is most of the mass in an atom? The mass is distributed evenly within the atom. The mass is mostly in the outside orbits, where the electrons are. The mass is mostly in the center of the atom, where the nucleus is. What is the total charge of an atom? positive negative neutral Explain why an atom has the charge you chose in the previous question? Is it possible to know the precise location of an electron? Yes No Why is it possible possible to identify the precise location of an electron at any given moment?