state dobereiner law of triads giving one example
Answers
Answer:
Dobereiner's law of triads states that, the atomic mass of the middle element of a triad is the arithmetic mean of the atomic masses of the other two elements.
Example:In the triad of lithium, sodium and potassium. The atomic mass of lithium is 7 and the atomic mass of potassium is 39.
Dobereiner stated in his law of triads that the arithmetic mean of the atomic masses of the first and third element in a triad would be approximately equal to the atomic mass of the second element in that triad. He also suggested that this law could be extended for other quantifiable properties of elements, such as density.
The first of Dobereiner’s triads was identified in the year 1817 and was constituted by the alkaline earth metals calcium, strontium, and barium. Three more triads were identified by the year 1829. These triads are tabulated below.
Triad 1
This triad was made up of the alkali metals lithium, sodium, and potassium.
This triad was made up of the alkali metals lithium, sodium, and potassium.Triad Atomic Masses
This triad was made up of the alkali metals lithium, sodium, and potassium.Triad Atomic MassesLithium 6.94
This triad was made up of the alkali metals lithium, sodium, and potassium.Triad Atomic MassesLithium 6.94Sodium 22.99
This triad was made up of the alkali metals lithium, sodium, and potassium.Triad Atomic MassesLithium 6.94Sodium 22.99Potassium 39.1
The arithmetic mean of the masses of potassium and lithium corresponds to 23.02, which is almost equal to the atomic mass of sodium.
Triad 2
As mentioned earlier, calcium, barium, and strontium formed another one of Dobereiner’s triads.
As mentioned earlier, calcium, barium, and strontium formed another one of Dobereiner’s triads.Triad Atomic Masses
As mentioned earlier, calcium, barium, and strontium formed another one of Dobereiner’s triads.Triad Atomic MassesCalcium 40.1
As mentioned earlier, calcium, barium, and strontium formed another one of Dobereiner’s triads.Triad Atomic MassesCalcium 40.1Strontium 87.6
As mentioned earlier, calcium, barium, and strontium formed another one of Dobereiner’s triads.Triad Atomic MassesCalcium 40.1Strontium 87.6Barium 137.3
The mean of the masses of barium and calcium corresponds to 88.7.
Triad 3
The halogens chlorine, bromine, and iodine constituted one of the triads.
The halogens chlorine, bromine, and iodine constituted one of the triads.Triad Atomic Masses
The halogens chlorine, bromine, and iodine constituted one of the triads.Triad Atomic MassesChlorine 35.4
The halogens chlorine, bromine, and iodine constituted one of the triads.Triad Atomic MassesChlorine 35.4Bromine 79.9
The halogens chlorine, bromine, and iodine constituted one of the triads.Triad Atomic MassesChlorine 35.4Bromine 79.9Iodine 126.9
The mean value of the atomic masses of chlorine and iodine is 81.1.
Triad 4
The fourth triad was formed by the elements sulfur, selenium, and tellurium.
The fourth triad was formed by the elements sulfur, selenium, and tellurium.Triad Atomic Masses
The fourth triad was formed by the elements sulfur, selenium, and tellurium.Triad Atomic MassesSulfur 32.1
The fourth triad was formed by the elements sulfur, selenium, and tellurium.Triad Atomic MassesSulfur 32.1Selenium 78.9
The fourth triad was formed by the elements sulfur, selenium, and tellurium.Triad Atomic MassesSulfur 32.1Selenium 78.9Tellurium 127.6
The arithmetic mean of the masses of the first and third elements in this triad corresponds to 79.85.
Triad 5
Iron, cobalt, and nickel constituted the last of Dobereiner’s triads.
Triad Atomic Masses
Triad Atomic MassesIron 55.8
Triad Atomic MassesIron 55.8Cobalt 58.9
Triad Atomic MassesIron 55.8Cobalt 58.9Nickel 58.7
Triad Atomic MassesIron 55.8Cobalt 58.9Nickel 58.7However, the mean of the atomic masses of iron and nickel corresponds to 57.3.
Limitations of Dobereiner’s Triads
The key shortcomings of Dobereiner’s method of classifying elements are listed below.
The key shortcomings of Dobereiner’s method of classifying elements are listed below.The identification of new elements made this model obsolete.
The key shortcomings of Dobereiner’s method of classifying elements are listed below.The identification of new elements made this model obsolete.Newly discovered elements did not fit into the triads.
The key shortcomings of Dobereiner’s method of classifying elements are listed below.The identification of new elements made this model obsolete.Newly discovered elements did not fit into the triads.Only a total of 5 Dobereiner’s triads were identified.
The key shortcomings of Dobereiner’s method of classifying elements are listed below.The identification of new elements made this model obsolete.Newly discovered elements did not fit into the triads.Only a total of 5 Dobereiner’s triads were identified.Even several known elements did not fit into any of the triads.
The key shortcomings of Dobereiner’s method of classifying elements are listed below.The identification of new elements made this model obsolete.Newly discovered elements did not fit into the triads.Only a total of 5 Dobereiner’s triads were identified.Even several known elements did not fit into any of the triads.Owing to these shortcomings, other methods of classifying elements were developed.
hope this helps you
please mark the answer as brainlest
please follow me