Question

an element x has a mass number 4 and atomic number 2 find the valency of x

Answer 1

Valence means the no. Of electrons that need to complete an octave ( it includes loss and gain of elections)
So in this there is no need of electron that the first octave is full.
So the valency is zero...

Answer 2

HEY DEAR ... ✌

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We know that only valence electrons take part in bond formation with different atoms.In the atom of 'X' element there are only two electrons since atomic number is 2. Thus, K shell is fully filled for this atom.Hence,its valency is zero. It will not react with other atoms of different elements

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