The properties of an element is a function of the combination of atoms and the levels of energy (or configuration) of the electrons.

For the purposes of this conversation we do not need to look any deeper then protons, neutrons, and electrons. So for now forget about Quarks.

So it goes like this.

Protons, neutrons, and electrons make up all atoms.
Atoms can combine to make elements.

We should all be familiar with elements not only from science class, but from the world around as such as oxygen!


What gets tricky is that elements combine to make molecules. Molecular chemistry is some pretty cool and complex stuff.

But that is what you expect from a system capable of producing such sophisticated things . . .

When say a single atomic nucleus is floating around and it has the simplest configuration ie One proton and one electron, then it is hydrogen.

Protons have positive charge and thus attract electrons which have a negative charge. Protons repel each other and so by themselves do not form more complex elements.

This is where neutrons come in, neutrons and protons belong to a group of particles called hadrons. A hadron is simply a particle that feels the strong, or nuclear force.

The nuclear force is an extremely short ranged, yet extremely strong force. Think of magnets, yet super strong and such a short ranged force that it only emits its field over distances of the diameter of the nucleus itself.

So when neutrons get close enough to protons the strong nuclear force will lock them together. This means that anytime kinetic energy enters a system with protons and neutrons that if they get knocked around enough to get 2 protons and 2 neutrons close together, then BAM, you have helium.

This discussion started as a question about stability and so that is where I will go with this.

There are nine configurations of helium or eight isotopes, however only 2 isotopes are stable.

He-3, and He-4.

He-4 is the most common isotope found on earth and is created due to alpha particle decay of unstable elements such as radioactive elements such as uranium.

To be a radioactive element really means to be unstable. The larger the element, means it has more protons and neutrons, the more protons and neutrons means that the jigsaw puzzle has more pieces, and more ways to be unstable.

This is why the most radioactive elements are also the heaviest. (generally speaking)

[edit: Billy beat me to this, but rather than just delete it, I'll leave it. N.B. if there's anything in my post that contradicts what Billy said, take his word for it, not mine. )]


Not quite.

Atoms are made up of Protons, Electrons and Neutrons.

Molecules are made up of atoms.

When molecules form, the atoms don't change. They just "lock together". (Or "unlock" when the molecule breaks apart.)

You could think of atoms as indivdual Lego pieces and molecules as groups of connected Lego pieces.

The pieces themselves don't change, only the "attachements" change. These changing attachments are what we call "chemical reactions".

Now the pieces could be changed by cutting them apart or gluing them together. But those processes actually change the pieces themsleves, not the relationships between pieces. Those processes are call "nuclear reactions".

UC Berkeley lectures on Radioactivity.
http://www.youtube.com/watch?v=EVB0F7kORII
http://www.youtube.com/watch?v=EHwpqszz-Rc

in the end every thing turns into helium

If there was no gravity, then this would be true.

But because gravity can crush hydrogen & helium and make heat it can make heavier elements. Then when the fusion runs low and gravity crushes the star further it will explode with huge energies and create even heavier elements such as uranium.

The same exact uranium that has decayed to create H-4 was born in a super nova explosion, the same uranium that was used in the bomb on Hiroshima was created in a much bigger explosion.