The electron cloud model describes the of electrons in an atom.

With help of electron cloud model, electrons location can be predicted.

Electron cloud is a casual method to portray a nuclear orbital. It is unique in relation to the more established Bohr nuclear model by Neils Bohr.  

The electron cloud model says that we can't know precisely where an electron is at some random time, however, the electrons are bound to be in explicit territories. In the Bohr model, electrons were allocated to various shells. These shells clarified the rehashing examples of compound properties in the intermittent table. Utilizing quantum mechanics, scientific experts can utilize the electron cloud model to dole out electrons to various nuclear orbital. These nuclear orbital are not all circles.  

The electron cloud model was created in 1926 by Werner Heisenberg and Erwin Schrödinger. The model is an approach to help picture the most likely position of electrons in a molecule. The electron cloud model is at present the acknowledged model of an atom.

it means there are 3 atoms of oxygen

it is the most commonly accepted one