Development of the Periodic Table
- Created by: HannahPorter2018
- Created on: 22-03-18 15:08
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- Development of the Periodic Table
- Early 1800s.
- Scientists didn't know about atomic structure, including; protons, neutrons and electrons, and they had no atomic numbers.
- All known elements were arranged in order of increasing relative atomic mass.
- When this was done, a periodic pattern was noticed in the propertied of the elements, hence the name "periodic table".
- Early periodic tables were incomplete, and some elements were placed in the wrong group.
- This was because elements were placed in order of relative, without taking into account their properties.
- Dmitri Mendellev
- In 1869, Dmitri Mendeleev took 50 known elements and arranged them into his Table of Elements, leaving various gaps.
- He put elements mostly in order of atomic mass, but did switch the order if the properties meant it should be changed.
- Gaps were left in the table to ensure that elements with similar properties remained in the same groups.
- Some of these gaps indicated the existence of undiscovered elements.
- They allowed Mendeleev to predict what their properties may be.
- When they were found and fitted the pattern, it helped to confirm Mendeleev's ideas.
- Some of these gaps indicated the existence of undiscovered elements.
- In 1869, Dmitri Mendeleev took 50 known elements and arranged them into his Table of Elements, leaving various gaps.
- Early 1800s.
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