Dobereiner's Triad & Law of Octaves

Which set of triads DOES NOT fit Dobereiner's Law of Triads?

• lithium, sodium, potassium

• calcium, strontium, barium

• phosphorus, arsenic, antimony

• chlorine, bromine, iodine

The Newlands' law of octaves for the classification of elements was found to be applicable only up to the _______ element

• potassium

• calcium

• cobalt

• phosphorus

In which order do we need to put sodium, potassium, lithium, for Dobereiner's Law of Triads ?

• lithium, sodium, potassium

• sodium, lithium, potassium

• potassium ,lithium, sodium

• sodium, potassium, lithium

The 'law of octaves' was enunciated by:

• Lother Mayer

• Mendeleev

• Dobereiner

• Newlands

On the basis o Newlands classification of elements, the properties of sulphur are similar to those of oxygen because sulphur is the______ element starting from oxygen.

• 7th

• 8th

• 3rd

• 6th

On what basis were the elements arranged in Dobereiner's triads ?

• atomic number

• atomic mass

• electron number

• number of electrons

How many traids did Dobereiner identify among the known elements?

• 5

• 3

• 2

• 1

Given that X, Y, Z are triads. Atomic masses of X and Z are 32,125 respectively. Then what is the atomic mass of Y is?

• 157

• 93

• 78.5

• 75.5

A & B are two elements having similar properties which obey the law of octaves. How many elements are there in between A and B?

• 6

• 7

• 8

• 5

If two members of a Dobereiner traid are calcium and stroncium, the third member of the triad is:

• cesium

• magnesium

• barium

• sodium