Here's why:

* The nucleus is the central core of an atom, containing protons and neutrons.

* Protons are positively charged, and neutrons have no charge.

* These particles are bound together by the strong nuclear force, an incredibly powerful force that overcomes the electrostatic repulsion between the protons.

* This force holds the nucleus incredibly tightly, meaning the protons and neutrons are essentially fixed in place.

While the nucleus can vibrate slightly, it's essentially a stationary, dense core within the atom.

In contrast, electrons are much smaller and negatively charged particles that orbit the nucleus. They have much more freedom of movement than the protons and neutrons in the nucleus.