Question

1)Johann Doberiner gave the idea of trends among physical 15.
and...X... of several groups of three elements. Here, X refers to
(a) atomic number (b) atomic mass
(c) chemical properties (d) None of these

2) Which of the following is the correct set of elements to
Dobereiner's triads?
(a) Li Na K
(b) Br CII
16.
7 23 39
80 35.5 127
(C) Fe Nico (d) Data insufficient
55.85 58.71 58.93

3) On which of the following Dobereiner 's Triad law is not
applicable?
(a) CI, Br, 1
(b) Ca, Sr,B
(c) F, CI, Br
(d) Li, Na, K

4) Newlands could classify clements only upto -
(a) copper
(b) chlorine
(c) calcium
(d) chromium
​

Answer 1

Answer:

1. atomic mass

2. Li Na K

3. Cl Br 1

4. Chlorine

Answer 2

Answer:a) atomic mass. - only modern periodic table is based on physical and chemical properties of atomic number rest all were based on atomic mass and hence they all had drawbacks.

b) Li Na K according to Dobereiner law in the triad the atomic mass of 1st and 3rd element average should be equal to atomic mass of 2nd element.

c) Fe, Cl Br

d) Ca