The ancient Greeks knew about the atom. Thru a simple thought experiment, not a physical one. They were brilliant that way. I read about it in an intro to chemistry class in community college in 1996. If you take a glass of water and divide it in half, you get two glasses of water. If you do it again, you have four, etc. If you keep doing that, you have to eventually stop. Because, they pointed out, nothing could be divided forever. And what you get, they said, would be called the atomos, or that which cannot be divided or cut further. Our atom. The book also said, that when they took this thought experiment a couple of steps further, they figured out that atoms could be combined and then separated. And that they probably had things orbiting around them. Electrons, we'd call them today. German physicist Johann Wolfgang Döbereiner actually made one of the earliest attempts to classify the elements. In 1829, he found that he could form some of the elements into groups of three. But in 1864, English chemist John Newlands showed that the known elements were periodical, or could be arranged in the order of their atomic weights and other properties. When people pointed out that there were gaps in his table, he said those must be spots for elements that haven't been discovered yet. There is no way to actually see an atom or molecule. Bacteria are microscopic. Viruses are submicroscopic. Atoms and molecules are even smaller than that. They probably are spherical, one guy on a message board once told me. But they have no color. They are so small, that light waves literally just bounce around them.
This is a cool link that I have used to understand the atom. Simple and easy to understand. The Particle Adventure | What is fundamental? | Fundamental
Some atoms can be split. Unstable isotopes will under go spontaneous decay and often form different elements. U-235 splits into barium and krypton. This can occur naturally or it can be helped along. In a controlled manner it is used in nuclear power plants. In an uncontrolled manner it becomes a nuclear bomb.
They also seemed to work out that when two elements combined to form more than one compound, the ratios were whole small numbers. This may have been the key to early understanding of valency.
When it was all about a certain number of protons, matched with the same number of electrons, forming an element, that was OK. Say that there are neutrons in there too, and the number of neutrons defines an isotope, and I could manage that. But now it's all about quarks, and I'm totally lost. Frankly they don't seem to be necessary at all, but they say we have to have them.
Yeah, but we are overemphasising it by looking in the mirror from modern knowledge standpoint. That was one of the many philosophical theories, and was not any better or worse than any other at the time. There was atomism in other philosophical cultures too, not just Greek. Ultimately if you have people thinking about something there is a limited number of possible solutions and interpretations, and some will turn out to be right. But that is luck, not knowledge. Also no ancient atomistic theory is exactly consistent with modern scientific ones.
I don't know. I just know I took an intro to chemistry class in community college in 1996. And our text book said, very plainly, that the ancient Greeks knew about the electron. That they knew there must have been something circling around the nucleus of that atom. I was surprised when I learned that myself then. But the text book didn't go into any detail about that. As I said, the text book seem to claim that the ancients knew about the electron. But sometimes when people talk about science and history, they are being more poetic, and maybe exaggerating a little. Like on another message board, I was shared a famous quote, where someone said infinity is where parallel lines meet. A board member said that really isn't true. Parallel lines could by definition never meet. He was just being poetic when he said that. Also, not to digress, but I still wonder. Did the guy who made that above quote mean perhaps mean asymptotic lines? That's what I first thought. Because asymptotic lines are kind of like parallel lines. I guess. And mathematicians claim that asymptotic lines do eventually meet. When they reach infinity, that is.
I don't think that is correct. AFAIK Greek atomism believed the atom to be the smallest division - and it is a philosophical stance, not something actually detected. Believed to be single elements of different shapes (like cones, triangles, whatever) in vacuum. I don't think electrons appear anywhere before late 19th century.
It was almost 30 years ago. And the text book author did say that. That the ancient Greeks said atoms spun around and combined, and had something spinning around them, the electron IOW. If I knew the name of the book or author, I'd look it up. I know sometimes if you remember a key word, maybe a word or a subject that only that author used, that might help in a Google search. And then maybe I could find an online version of that text book and post the text and provide a link too.
