The Periodic Table
- Created by: saoirse: )
- Created on: 04-03-15 17:01
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- The Periodic Table
- The Early Periodic Table
- in the 19th century (1800) less than 40 elements had been discovered.
- New ones were being discovered regularly
- The scientists started to see a pattern in the way the elements reacted
- One of the first scientists to publish a version of the table was a English scientist called John Newlands
- he arranged them in 'law of octaves'
- he noticed that every 8th element had similar properties.
- The law of octaves only worked for the first few elements.
- left out that there were more elements to be discovered.
- he arranged them in 'law of octaves'
- Scientists worked out properties like the atomic mass.
- A Russian scientist Dmitri Mendeleev arranged the elements in periodic way.
- he left gaps where he thought new elements would be discovered.
- he predicted the atomic masses and other properties of undiscovered element's
- No group 0 as the noble gasses hadn't been discovered yet
- The Modern Periodic Table
- More elements were discovered
- We order the elements today with the atomic number
- the elements in the same group have similar properties.
- middle block are is the transition metals
- compared to group 1 they have
- a higher melting and boiling point (except for mercury)
- they are harder and stronger
- good to be used for structural materials
- are much less reactive and so don't react so much with water and oxygen
- they can form ions with different charges
- they form coloured comounds
- they are useful as catalysts
- compared to group 1 they have
- the groups are arranged by the number of electrons on their outer shell.
- Group 0 have a full outer shell of electrons
- Group 1 are the Alkali metals
- Low density
- React with non-metals to form ionic compounds
- will produce a ion with a +1 charge
- React with water to produce hydrogen
- The further down the group you go:
- the lower the melting and boiling point
- the more reactive the element
- More elements were discovered
- The Early Periodic Table
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