Question

what aspect of Bohr's original model of election stucture is no longer considered valid in the currently accepted theory of electron structure

Answer 1

Bohr suggested circular orbits of electrons around the nucleus of hydrogen atom, but researches have shown that motion of electron is not in a single plane., but it takes place in three dimensional space. Actually, the atomic model is not flat

Answer 2

Bohr's original model stated that electrons were tiny little objects circling the nucleus along fixed orbits, however this is no longer valid as we now know that rather "circling" the nucleus at confined orbits, electrons can seem to be everywhere at once.