Why is it accurate to say that an atom is mostly composed of empty space?

• A. Because atoms are made entirely of protons and neutrons tightly packed together.
• B. Because the nucleus is extremely small compared to the overall size of the atom, and electrons occupy regions of space far from the nucleus.
• C. Because the atomic mass is distributed evenly throughout the atom.
• D. Because electrons fill all available space within the atom.

Answer: (B)

Verified step by step guidance

1. Understand the structure of an atom: it consists of a tiny, dense nucleus containing protons and neutrons, surrounded by electrons that occupy a much larger volume.
2. Recognize that the nucleus is extremely small compared to the overall size of the atom; the radius of the nucleus is on the order of 10^{-15} meters, while the atomic radius is about 10^{-10} meters.
3. Know that electrons do not orbit the nucleus like planets but exist in probabilistic regions called orbitals, which define the space where electrons are likely to be found.
4. Since the nucleus occupies a minuscule fraction of the atom's volume and electrons are spread out over a large region, most of the atom's volume is empty space.
5. Therefore, it is accurate to say an atom is mostly empty space because the dense nucleus is very small and the electrons occupy a large, mostly empty region around it.