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The periodic law, as we know it today, o...

The periodic law, as we know it today, owes its development to two chemists.
(i) John Newlands (ii) Dmitri `I`. Menseleev
(iii) `J`.Lothar Meyer (iv) `J.W`. Dobereiner

A

Rutherford and Moseley

B

Alexander newlands and doberiner

C

Dmitri mendeleev and lothar meyer

D

De broglir and Neil bohr.

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C
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NCERT FINGERTIPS-CLASSIFICATION OF ELEMENTS AND PERIODICITY -Assertion And Reason
  1. The periodic law, as we know it today, owes its development to two che...

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  2. Assertion:According to mendeleev,the properties of elements are a peri...

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  3. Assertion:Atomic number is a more fundamental property of an element t...

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  4. Assertion:Atomic number of the element ununtrium is 113. Reason:Accor...

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  5. Assertion:In the present form of periodic table,the period number corr...

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  6. Assertion:The chemistry of the early actinoids is more comlicated than...

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  7. Assertion:The atomic size generally increases across a period and decr...

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  8. Assertion:Among isoelectronic species,the cation with the greater posi...

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  9. Assertion:On moving down the group the group,ionization enthalpy decre...

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  10. Assertion:For the elements O or F,the electron gain enthalpy is less n...

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  11. Assertion: Shielding effect increases as we go down the group. Reaso...

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  12. Assertion:Electronegativity is not a measurable quantity. Reason:The e...

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  13. Assertion:Oxidation state of oxygen in OF(2) and Na(2)O is +2 and -2 r...

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  14. Assertion:Boron can only form [BF(4)]^(-),whereas aluminium forms[AIF(...

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  15. Assertion:Metallic character is highest at the extremely left side of ...

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  16. Assertion:Na(2)O is basic whereas Cl(2)O(7) is acidic oxide. Reason:E...

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