Question: Write in a tabular form the 1871 version of Mendeleev’s periodic table.
Table: Mendeleev’s Periodic Table (1871 version)
Question: Collect information about the properties of the predicted elements by Mendeleev and the observed properties of these elements discovered later. (2 Marks)
Answer:
Question: Give Newlands table of elements. Write a brief note about the arrangement of elements in it.
Answer: Table: Newlands table of elements
Elements with similar chemical properties are to be present along a horizontal row.
Newlands was the first to assign atomic numbers to the elements. Unfortunately his work was neither accepted by his seniors nor by the journal of the chemical society, which rejected its publication.
In Newlands table of elements, if we start with hydrogen and move down and then start at the top the eighth element is fluorine and next eighth element is chlorine and so on.
The properties hydrogen, fluorine and chlorine are similar. Similarly, if you start at Lithium, then eighth element is sodium and next coming eighth is potassium and so on. These elements show similar physical and chemical properties.