An atom of element x has one more shell of electrons than an atom of beryllium, but it has one less valance electron than beryllium. which element is x

The atomic number of Be is 4, and so it has 2 shells. There are valence electrons in the second, which is the outermost, shell of Be. To get the element with one more shell, there would be 3 shells on the new element, and 1 less valence electron, so the new element should have 1 valence electron. Sodium is the element with 3 shells, and one valence electron which fits perfectly into the description.

Answer it is also known as the completion state is untrue of the activation complex;

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