Law of Octaves

To know the Law of Octaves, we must first know what an Octave is?

Lets us now Define Octave: It could be defined as arrangement of eight note occupying the interval between two notes, wherein, one having twice or half the frequency of vibration of the other.

For example: In musical notes, after certain interval the note will repeat itself.

1	2	3	4	5	6	7
Sa	Re	Ga	Ma	Pa	Dha	Ni
Sa	Re	Ga	Ma	Pa	Dha	Ni

Now let us discuss Law of Octaves: It was proposed in the year 1865 by John Newlands (John Alexander Reina Newlands), British chemist, who classified the elements based on his law. According to the law, when elements placed in an increasing order of their atomic mass formula, every eighth element will show similarity in both physical and chemical properties. Since Newland proposed the Law of Octaves, in his honor the law is also called as Newlands Octaves.

We shall now study the Newlands Periodic Table; based on his law, Newlands arranged the known elements in a tabular form, wherein even row consists of seven elements and the eighth element was placed under the first element.

For example: The Newlands Periodic Table symbols is shown bellow, where in the lithium (Li) is the first element and the sodium (Na) is the eighth element, the Li and Na exhibit the similar physical and chemical properties, similarly, if we start arranging the elements in the increasing order of their atomic mass from Beryllium (Be) then the eight element would be Magnesium (Mg), both will exhibit similar chemical and physical properties.

Li	Be	B	C	N	O	F
Na	Mg	Al	Si	P	S	Cl
K	Ca

Newlands Periodic Table

Now we shall look into the drawbacks of the Newlands Octaves:

• The law does not hold good for the elements having atomic masses higher than calcium.
• Noble gases does not obey this law
• Classification was based on the atomic mass of an element is the periodic function of its chemical and physical properties concept.
• The law was valid till the Henry Moseley (1913), put forth the concept that the properties of an elements varies periodically according to the atomic number but not to the atomic mass.