Question

19. Which of the scientists given below discovered that 37
periodic table should be based on the atomic number?
(a) Mendeleev
(b) Newlands
(c) Moseley
(d) Lothar Meyer

20. How many elements are there in 6th period of periodic table?
(a) 18
(b) 8
(c) 30
(d) 32

21. Modern periodic table is based on the atomic number of the
elements. The experiment which proved the significance of
the atomic number was
(a) Mulliken's oil drop experiment
(b) Mosley's work on X-ray spectra
(c) Bragg's work on X-ray diffraction
(d) Discovery of X-rays by Rontgen

22. The period number in the periodic table corresponds to the
...A... principal quantum number (n) of the elements. Here, A
refers to
(a) lowest
(b) highest
(c) middle
(d) None of these​

Answer 1

Answer:

19.mendeleev

20.(a) 18

21.mosley work on x-ray spectra

22.highest

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Answer 2

Answer:

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Explanation:

19.It was Henry Moseley who suggested a better arrangement than Mendeleev. He arranged the elements according to their Atomic Number rather than their Atomic mass.

20. 32 are there in 6th period of periodic table