This series uses demonstrations and animations to take students on a journey of discovery to explain what we know about atoms-and how we know what we know about atoms. This fourth episode examines the discovery of atoms and the development of the periodic table. By explaining the basics of atoms, students can better understand the chemical reactions which led to their discovery. It also looks at the Mendeleev's predictions of atoms that were later confirmed.

Originally released by Liacos Educational Media, 2015. Streaming video file encoded with permission for digital streaming by Infobase on September 26, 2015. Link to website with Teacher's notes and Question Sheet for students available under Additional info tag.

The Periodic Table --(4:17) -- Classifying the Elements -- (3:18) -- Discovering With Electricity -- (4:40) -- Periodicity of Properties -- (7:08) -- Pattern Across the Periods -- (2:24) -- Prediction of New Elements -- (5:33) -- Formation of the Periodic Table -- (1:52) -- Credits: The Periodic Table: Shedding Light on Atoms, Episode 4 -- (2:25). Part A: Introduction: We look back briefly at the difference between elements and compounds and how Dalton came up with his atomic theory. Part B: Classifying the Elements: Elements, at a simple level, can be classified into two main groups: metals and non-metals. Some of the main differences between the two are demonstrated. Part C: Discovering with Electricity: Lavoisier’s 1780s list of elements contained only 24 elements. In 1800, Alessandro Volta invented the first battery. Electricity helped with the discovery of many new elements. Part D: A Periodicity of Properties: By 1869, scientists had discovered 63 different elements and this was enough for them to start seeing lots of different patterns in the way that they behaved chemically. Dmitri Mendeleev produced a table—the first Periodic Table—which didn’t just classify the elements as metals and non-metals but organized them into groups based on how they chemically react with oxygen and hydrogen. We look at how he achieved this remarkable scientific breakthrough. Part E : The Prediction of New Elements: Mendeleev’s organization of the elements into a Periodic Table was so good that he was able to predict the existence of elements that hadn’t been discovered and many of their chemical and physical properties.