Tag: chemistry

Questions Related to chemistry

Dobereiner grouped the elements into triads and Newland gave the:

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. law of Octaves

  2. mass number

  3. atomic number

  4. valency

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Correct Option: A
Explanation:

In 1864 newlands in chemistry, the generalization made by the English chemist J.A.R. Newlands in 1865 that, if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements. Newlands was one of the first to detect a periodic pattern in the properties of the elements and anticipated later developments of the periodic law. Hence called law of octaves.

Newland could classify elements only upto :

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. copper

  2. chlorine

  3. calcium

  4. chromium

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Correct Option: C
Explanation:

He observed that every eighth element had properties similar to the first element. Elements after atomic no. 40 do not fit in this rule.

The discovery of which of the following group of elements gave a death blow to the Newland's Law?

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. Inert gases

  2. Alkali metals

  3. Transuranic element

  4. Halogens

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Correct Option: A
Explanation:

The discovery of zero group of elements (inert gases) gave a death blow to the Newland's Law.
According to Newlands Law of octaves, when the elements are arranged in the increasing order of atomic weights, the properties of every eighth element are similar to the first one.


Hence, the correct option is $\text{A}$

Which of the following pairs of elements do not follow octave rule?

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. $Be, B$

  2. $Ca, Sr$

  3. $F, Cl$

  4. $O, S$

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Correct Option: A

X and Y are two elements having similar properties which obey Newlands law of octaves. The number of elements in between X and Y respectively are:

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. 8

  2. 6

  3. 7

  4. 9

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Correct Option: B

The standard emf of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V at 25C°. The equilibrium constant of the reaction would be
(Given, $F = 96500 C mol^{-1}, R = 8. 314 JK^{-1} mol^{-1}$ )

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. $2.0\times 10^{11}$

  2. $4\times 10^{12}$

  3. $1\times 10^{2}$

  4. $1\times 10^{10}$

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Correct Option: D
Explanation:

The Newland's law of octaves for the classification of elements was found to be applicable only up to the element ______________________.

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. potassium

  2. calcium

  3. cobalt

  4. phosphorous

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Correct Option: B
Explanation:

The Newland's law of octaves for the classification of elements was found to be applicable only up to the element calcium.


Law of octaves, in chemistry, the generalization made by the English chemist J.A.R. Newlands in 1865 that, if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements.

 Newlands was one of the first to detect a periodic pattern in the properties of the elements and anticipated later developments of the periodic law.

The elements $A$ and $B$ obey Newland's law of octave. How many elements are there between $A$ and $B$?

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. 7

  2. 8

  3. 5

  4. 6

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Correct Option: D
Explanation:

According to the law of octaves, those with similar physical and chemical properties occur after each interval of seven. 


Thus if $A$ is the first element and $B$ is the eighth element, the number of elements in between $A$ and $B$ is 6.

Hence, option D is correct.

The element which resembled cobalt, nickel and was placed in Newland's table far away from those elements was:

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. sodium

  2. calcium

  3. iron

  4. chlorine

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Correct Option: C
Explanation:

Iron resembled cobalt and nickel and in Newlands' table was placed far away from those elements. It was placed in the last group in Newlands' table.

The element placed with nickel in the table formed by Newlands was :

chemistry the periodic table newland's law of octaves development of the modern periodic table into the history

  1. iron

  2. cobalt

  3. chromium

  4. copper

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Correct Option: B