Development of Periodic Table

• John Newlands tired to put together a periodic table in 1864
• When John Newlands tried to put together a periodic table in 1864, only 63 elements were known - many were still undiscovered
• John Newlands arranged the known elements in order of atomic weight
• Periodicity is repeated patterns
• When trying to put together a periodic table, he noticed periodicity , although the missing elements caused problems
• When Newlands created the periodic table, strictly following the order of atomic weight caused issues - it meant some of the elements were in the wrong place
• Dimitri Mendeleev realised that some of the elements had yet to be discovered
• When Dimitri Mendeleev created his periodic table in 1869 , he left gaps to allow for the unknown elements to be discovered
• When did Dimitri Mendeleev create his Periodic Table?

  1869
• When creating his periodic table, Dimitri Mendeleev reordered some of the elements
• When Dimitri Mendeleev created his periodic table, each element was placed in a vertical column known as a group ,
• In his periodic table, Dimitri Mendeleev created groups, where elements that had similar properties where placed in
• Mendeleev used his periodic table to predict the existence and properties of new elements
• When the subatomic particles were later discovered, it revealed that Mendeleev had organised the elements in order of increasing atomic number (number of protons)
• Elements that have the same number of electrons in their outer shell have similar properties
• In the periodic table, elements with the same number of electrons in their outer shell are in the same group