Saturday, 21 January 2017

More about particles- protons and electrons in atoms

One characteristic of the fundamental particles is that whenever we detect them individually they seem to be very tiny point-like objects. That is, they seem to be solid and compact like a billiard ball, rather than long and stretched out like a hose-pipe or a bed-sheet, or smeared like a cloud of steam. However, we'll see later that according to quantum theory the idea of the particles being like little points of matter is too simple, but that's the idea we will continue to work with for now.

Protons are about 2,000 times heavier than electrons. In atoms, the protons seems to be clustered tightly together at the centre- called the nucleus- while the electrons are more widely spread around the nucleus.

We used to think that the electrons circled around the nucleus of protons like planets orbiting the Sun, and for now that's a good image to have in your head.

What's surprising is that when atoms come together to form a solid- imagine a lump of gold say- there's still relatively huge gaps between their heavy centres. If the nucleus of an atom of gold was the size of a grapefruit, say, then the atoms in gold would be about a kilometre apart, with the electrons somehow buzzing around in the space between them. It's odd to consider that something that seems as solid and heavy as gold is actually mainly empty space!

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