How did the development of quantum mechanics change Bohr's model of the atom? a Instead of being spread evenly throughout the atom, the electrons were in a cloud around the outside. b Instead of being a broad cloud of electrons, the electrons were organized into discrete levels, or shells. c Instead of being in open shells, the electrons were placed into orbitals based upon their probability distribution. d Instead of being on the outside of the atom, the electrons were found to be in a separate space