C3

The Periodic Table

What we already know:

elements are represented in the periodic table and consist of atoms, which are represented using chemical symbols

elements are arranged in the table according to their reactivity and properties.

What we need to know:

- The early periodic table

- The modern periodic table

- Group 1

- Group 7

The early periodic table

In the 19th century scientists were trying to find patterns in elements in order to organise them. they found a new element almost every year.

one suggestion was to arrange them in order of masses measured in various chemical reactions.

a later theory built on this idea, and used the idea of octaves (in music it is 8 notes) as a scientist observed that every 8th element seems similar

the octave idea was not accepted as the scientist changed the data he had collected, and had not accounted for the fact that new element were still being discovered.

in 1869 a Russian scientist Dmitri Mendeleev…