Question

an element is represented as X 40,20 name the shell which has Valence Electrons and the number of valence electrons in it

Answer 1

Hi frnd..........

Electronic configuration of element X = 2,8,8,2

     So, we can say that the valence electron is in 4th (N)shell.

The no of valence electron in it is 2 

Hope this helps ................. :D

Answer 2

4th shell will have 2 valence electrons.

• As per the given information, the mass number of element X is 40 and the atomic number of element X is 20.
• The electronic configuration as per the atomic number will be 2,8,8,2.
• Hence, there will be 4 shells in the element.
• The outermost shell will have 2 electrons. These electrons participate in the reaction. Thus, the valency of element X will be +2.

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