What Does An Atom Look Like?

There are now imaging technologies that enable scientists to focus down to the level of a single atom, but the images are still very murky and hard to interpret.

Our knowledge of what an atom looks like stems more from our knowledge of what it contains and how it behaves. The atom of every element on Earth contains a central nucleus, which houses the particles called protons (which are positively charged) and the particles called neutrons (which are negatively charged).

Around this central nucleus there are orbiting electrons (which carry a negative charge). The number of protons and the number of electrons in an element is the same, so the positive and negative charges cancel each other out.

Different elements have different numbers of protons and neutrons and electrons. Lithium, for example, has an atomic number of 3, which means it has 3 protons and 3 electrons. It has an atomic mass of 7 (this is the number of protons and neutrons added together), which means it has 4 neutrons. One can therefore imagine a nucleus of lithium with three protons and four neutrons, orbited by three whizzing electrons. The scale is difficult for most people, but if you imagine a large classroom in a school with the nucleus the size of a pea, the electrons will be orbiting in a sphere around the classroom walls.

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It is the smallest part of the molecule, retaining the same property as the molecule. It is so small that it cannot be seen with the naked eye.

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