If all matter were composed of electrically neutral particles like...

The normal force, tension in a string, and the force of friction are all macroscopic manifestations of the electromagnetic force between atoms and molecules. If all matter were composed of electrically neutral particles, electromagnetic forces would cease to exist. Consequently, normal force, tension, and friction would be absent.

The gravitational force depends only on mass and is independent of electric charge. Since neutral particles like neutrons possess mass, the gravitational force would still exist. Thus, the earth would continue to move around the sun.