Atoms are on package deal: they consist of protons, neutrons and electrons. Electrons are small but mighty, contributing very little to the atom’s mass but hugely influencing physical phenomena like electricity, magnetism, and chemistry. Most atomic illustrations, like ours, show electrons orbiting atomic nuclei like planets around the Sun. That’s an intuitive way to think about it, but it’s not actually what’s happening. An electron shell is actually a probability distribution for where you’re most likely to “find” the electron at any moment.
Electrons, like all fundamental particles, don’t actually have a true intrinsic size. This is one common approximation physicists use for working with them.
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