What is the most current model of how the atom is constructed?
1. a donut shaped cloud of protons surrounding a dense nucleus containing electrons and neutrons
2. a loose collection of protons, neutrons and electrons all mixed up into a sphere
3. a dense nucleus of protons and neutrons surrounded by electron clouds of different shapes and sizes 4.
a miniature solar system with the sun replaced by a dense nucleus made of protons and neutrons, with the electrons orbiting like planets

3. A dense nucleus of protons and neutrons surrounded by electron clouds of different shapes and sizes.

Explanation:

In the nucleus of an atom there are protons an neutrons densely packed together, while the electrons move around this nucleus.

The difference between answer 3. and 4. is that the electrons do not follow an established orbit, like planets do. They are too small and move too quickly for us to precisely determine both their position and their speed, at any given time. This is why they are thought to be electron clouds.