Dobereiner's Triads

Q. According to Dobereiner's theory of triads, the mass of middle element was roughly the average of atomic masses of other two elements.

1. False
2. True

Q.

Assertion; Elements $Li,Na$ and $K$constitute a triad.

Reason: Atomic mass of Na is nearly mean of the atomic mass of $Li$ and $K.$

Mark the correct choice as

1. Both assertion and reason are true and the reason is the correct explanation of assertion.

2. Both assertion and reason are true but the reason is not the correct explanation of assertion.

3. Assertion is correct but the reason is incorrect.

4. Assertion is incorrect but reason is correct

Q. Dobereiner arranged similar elements in a group of three , i.e, triads, on the basis of?

1. Nearly the same atomic weight
2. The atomic weight of the third element was approximately the arithmetic mean of the first two elements
3. The atomic weight of the middle element was approximately the arithmetic mean of the other two elements
4. Both $\left(a\right)$ and $\left(c\right)$

Q. Identify the element 'X' from the dobernier triad given below:

Element	Chlorine (Cl)	X	Iodine (I)
Atomic Mass (A)	35.5	Y	126.9

1. X : Bromine
   Y : 82.0
2. X : Fluorine
   Y : 82.0
3. X : Fluorine
   Y : 79.9
4. X : Bromine
   A : 79.9

Q. Atomic mass of X and Z is 20 and 40 respectively. If X, Y and Z form a Dobereiner's triad then the value of Y is

1. 20
2. 30
3. 40

Q. Which of the given statement(s) are correct in accordance to Doberenier traids?

1. The elements are written in increasing order of atomic mass.
2. The mass of middle element was roughly the average of atomic masses of other two elements.
3. Elements in the triads show similar properties.
4. All of the above.

Q. follows Dobereiner's law of Triads.

1. Sr, Ba, Ca
2. Br, Cl, I
3. Cl, Br, I

Q. Which of the following statement is not true about Doebereiner's Law of Triad?

1. The law was applicable to all known elements
2. Nitrogen family does not obey the law of triads
3. Doebereiner's classification was not very useful
4. The atomic mass of central element of each was merely the arithmetic mean of the atomic masses of other two elements.