History of the Periodic Table

We haven't always known as much about Chemistry as we do now (obviously); early chemists looked to try and understand patterns in the elements' properties to get a bit of understanding.

In the Early 1800s they could only go on atomic mass:

Whereas now there are two obvious ways to categories elements:

1. Their physical and chemical properties

2. Their relative atomic mass

REMEMBER - back then they had no idea about atomic structure or about protons and electrons meaning there was no such thing as atomic number.

(Only in the 20th century - after protons and electrons were discovered - that we realised the best arrangement was in order of atomic number)

Back then all they could measure was the relative atomic mass; this meant the known elements were arranged in order of atomic mass.

When this was done, a periodic pattern was noticed in the properties of the elements - it's where the name "Periodic Table" comes from (ta-da)

Newlands' Law of Octaves (the first good effort)

John Alexander Reina Newlands. (Pictured above)

H

Li

Be

B

C

N

O

F

Na

Mg

Al

Si

P

S

Cl

K

Ca

Cr

Ti

Mn

Fe

Newlands attempted to arrange things more usefully back in 1864. 

He noticed:

- Every eighth (8th) element had similar properties

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