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Earn 100

The number of elements known when Mendeleev presented periodic table is
(a)50
(b)90
(c)63
(d)102

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Important Questions on Periodicity
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Given Frequency of X-ray emitted
Atomic number

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Identify the incorrect match.
Name IUPAC | Official Name |
(a) Unnilunium | (i) Mendelevium |
(b) Unniltrium | (ii) Lawrencium |
(c) Unnilhexium | (iii) Seaborgium |
(d) Unununium | (iv) Darmstadtium |

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It is observed that characteristic X-ray spectra of elements show regularity. When frequency to the power 'n' i.e. of X-rays emitted is plotted against atomic number , the following graph is obtained.
The value of 'n' is

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