16 of 17

Write now Article Tools

Page 2 of 3

be stable and not fall apart or collapse on itself.

Neutrons are necessary as they contribute to the attraction within the nucleus without contributing to the repulsion, as neutrons have no charge. A large number of protons wouldn't be able to stay together with just their own nuclear forces, and so neutrons are needed for any atom with more than just one proton (the hydrogen nucleus is just one proton).

If atoms were just nuclei, then chemistry and this universe wouldn't exist in the same form all atoms would be positively charged, and so would repel each other. There might be elements, but there would be no molecules or larger groups of matter. There would be no life. Clearly, the explanation so far does not sufficiently explain how atoms "work". What we are missing is the electron.

Much smaller than the proton and neutron (which are of almost the same mass), the electron is a tiny particle with exactly the same quantity of charge as the proton, but of opposite polarity negative instead of positive. In a similar way to how planets can safely orbit stars, electrons orbit the nuclei of atoms, being attracted by protons. Electrons do not disturb the nucleus much and the nuclear force doesn't apply to them, so they don't upset the balance of the nucleus.

In actuality, electrons are far more complicated than this simplistic, outdated model, but the model is mostly adequate for discussion of chemistry. Being as small as they are, electrons are inhabitants of the strange and unintuitive world of quantum physics (they can be said to not so much move around in an orbit as disappear and reappear in a vague area completely randomly). It has also been found that the analogy of a planet orbiting a star while never being pulled in isn't quite true for the electron around the nucleus for mathematical reasons, and something called the Pauli exclusion principle is instead key to keeping electrons not just in place, but in neatly organised energy levels. (The exclusion principle fundamentally explains the entire periodic table, but calls upon a great deal of physics and isn't strictly necessary to an understanding of chemistry.)

An atom therefore has three parts: the nucleus, comprised of protons and neutrons in a tight balance of forces called an equilibrium; the electrons, zipping around rather randomly, and the empty space between it all. In fact, the vast majority of the area of space chemists call an atom is empty of mass, but it is awash with forces and is doing far more

• << previous page
• 1
• 2
• 3
• next page >>

Add your voice

Know something about How atoms work?
We want to hear your view. Write now!