No, J.J. Thomson did not come up with the electron cloud model. The electron cloud model was developed much later, after Thomson's "plum pudding" model.

Here's a breakdown:

* J.J. Thomson (1897): Discovered the electron and proposed the "plum pudding" model. This model imagined the atom as a sphere of positive charge with negatively charged electrons embedded within it.

* Ernest Rutherford (1911): Through his gold foil experiment, Rutherford disproved the plum pudding model. He proposed the nuclear model, which placed a positively charged nucleus at the center of the atom, with electrons orbiting around it.

* Niels Bohr (1913): Built upon Rutherford's model, introducing the idea of quantized energy levels for electrons. However, Bohr's model still depicted electrons as orbiting the nucleus in defined paths.

* Electron Cloud Model (1920s - 1930s): Developed based on the principles of quantum mechanics, the electron cloud model represents electrons not as particles orbiting a nucleus, but as probability distributions. This means that the location of an electron can't be known with certainty, only the probability of finding it in a particular region.

Therefore, the electron cloud model came about as a result of further advancements in atomic theory, building upon the work of scientists like Thomson, Rutherford, and Bohr.