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NTA Abhyas JEE Main2020ChemistryClassification of Elements and Periodicity in PropertiesPractice

The effective nuclear charge of an element with three valence electrons is 2.60. What is the minimum atomic number of the element?

Options

  1. A5
  2. B4
  3. C3
  4. D2

Correct answer

A. 5

Step-by-step solution

As effective nuclear charge is 2.60 and valence shell contain 3 electrons so the minimum number of main shells for the given element are two i.e., (n = 2) and its configuration will be 1 s 2 , 2 s 2 , 2 p 1 . Hence the given element has 5 electrons in all. Also, for a neutral atom. As number of electrons = atomic number = 5. Thus, the atomic number of the element is 5.

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