1. The Periodic Table http://www.youtube.com/watch?v=DYW50F42ss8
24 December, 2018
What is today’s lesson about?
The Periodic Table

2. The History of the Periodic Table

3. Lavoisier ( ) Complied the first extensive list of elements with his wife - Distinguished between metals and non-metals - Unfortunately included some compounds/mixtures & light/heat - He was branded a traitor during the French Revolution & was beheaded in 1794

4. John Dalton (1808) Dalton ordered 36 elements
He gave each element a symbol
The symbols were not easy to memorise

5. Johann Wolfgang Döbereiner (1829)
Döbereiner looked at the recently
discovered Bromine and saw it had
properties half way between chlorine
and iodine.
Döbereiner called these three elements a triad.
Döbereiner also saw that there were other triads

6. John Newlands (1864) Newlands created the ‘Law of Octaves’.
The known elements were arranged in horizontal rows, seven elements long, by increasing atomic mass.
Newlands stated the eighth element would have similar properties to the first in the series, but after Ca, failed in predicting a consistent trend.

7. Dimitri Mendeleev ( )
He had a set of 63 cards, one for each known element Mendeleev listed the known elements in rows or columns in order of atomic mass. Mendeleev started a new row or column if an element’s characteristics were repeated. Mendeleev's table succeeded, as he left gaps in his table if he thought an element had not been discovered.

9. The periodic table is ordered using proton number
The periodic table is ordered using proton number. Ordering the elements in this way produces repeating patterns in the properties of elements.

10. Groups Periods Transition elements 1 8 / 0 2 3 4 5 6 7
Do not react with anything
Increasing reactivity
Decreasing reactivity
Transition elements

11. Important points Horizontal rows are called periods Vertical columns are called groups Elements in the same group have similar properties This is because elements in the same group have the same number of electrons in their outer shell

12. Periodicity