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प्रश्न
What is Debereiner's law of triads? Explain with the help of one example of a Dobereiner's triad.
उत्तर
According to Dobereiner's law of triads, when elements are arranged in increasing order of their atomic masses, a group of three elements with similar chemical properties is obtained. This group is called a triad. The atomic mass of the middle element is equal to the arithmetic mean of the atomic masses of the other two elements.
For example, the set of elements: calcium (Ca), strontium (Sr) and barium (Ba), with atomic masses 40, 88 and 137 respectively form a triad because they have similar chemical properties, and the atomic mass of strontium is approximately equal to the average of the atomic masses of calcium and barium.
Arithmetic mean of atomic masses of calcium and barium =`(40+137)/2 =88.5`
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संबंधित प्रश्न
The arrangement of elements in a group of three is known as ________.
The three imaginary elements X, Y and Z represent a Dobernener's triad. If the atomic mass of element X is 14 and that of element Y is 46, then the atomic mass of element Z will be:
(a) 28
(b) 60
(c) 78
(d) 72
The atomic masses of three elements X, Y and Z having similar chemical properties are 7, 23 and 39 respectively.
(a) Calculate the average atomic mass of elements X and Z.
(b) How does the average atomic mass of elements X and Z compare with the atomic mass of element Y?
(c) Which law of classification of elements is illustrated by this example?
(d) What could the elements X, Y and Z be?
(e) Give another example of a set of elements which can be classified according to this law.
What was Dobereiner’s basis, of classification of elements?
Explain why Dobereiner’s method of classification of elements did not hold much weightage for future classification.
Find the odd one out and give its explanation.
Write the characteristic of Dobereiner’s triads?
According to Dobereiner’s triads rule, three elements in an increasing order of atomic mass shows _______.
State Dobereiner’s Law of Triads.
Match the following.
| 1. | Triads | Newlands |
| 2. | Alkali metal | Calcium |
| 3. | Law of octaves | Henry Moseley |
| 4. | Alkaline earth metal | Sodium |
| 5. | Modern Periodic Law | Dobereiner |
