Atoms are the most basic building blocks, everything around us are made out of atoms. Atoms are so small that it can’t be found under the finest microscopes. A tiny spec of dust contains millions of billions of atoms! Even though atoms are tiny, but it actually consist of three different particles: protons, neutrons, and electrons. In every atom, electrons move around the nucleus, the combination of protons and neutrons.
The idea of an atom was first discovered by the ancient Greeks, they used the word “atomos” to describe something that is uncuttable. This idea was not found by a scientist, but it was first used by the Greek philosopher Democritus. At that time, the technology did not support the scientist to actually conduct experiments, …show more content…
The first change was made by J.J. Thomson in 1897. He found negatively charged particles in atoms in an experiment, but atom itself should not have any charges. So he inferred that there are some other particles neutralizing the charge, he invented the word proton, which is positively charged, and negatively charged particles as electrons. He also revised the model, he predicted that electrons are attached to a ball of positive charges.
Still, he was proven wrong by his own student, Ernest Rutherford in 1911. According to his experiments, his team shot a positively charged beam at a gold foil, if Thomson’s model was correct, the ball of positive charges won’t be able to repel the beam (Like charge repel each other). Some were deflected strongly, so Rutherford thought that all the positively charges are packed in the middle of an atom. Two years later, a Danish scientist Niel Bohr proposed that electrons orbit in certain orbits. It seemed pretty advanced at that time, but it was soon proven incorrect. In the late 1920s, the cloud model was created. It stated that electrons don’t move in orbits, instead their motion were affected by energy levels. Soon, scientist found particles inside atoms that did not have any charges, called neutrons. Since neutron was neutral, it was really hard to detect. This model was named as modern
The idea of an atom was first discovered by the ancient Greeks, they used the word “atomos” to describe something that is uncuttable. This idea was not found by a scientist, but it was first used by the Greek philosopher Democritus. At that time, the technology did not support the scientist to actually conduct experiments, …show more content…
The first change was made by J.J. Thomson in 1897. He found negatively charged particles in atoms in an experiment, but atom itself should not have any charges. So he inferred that there are some other particles neutralizing the charge, he invented the word proton, which is positively charged, and negatively charged particles as electrons. He also revised the model, he predicted that electrons are attached to a ball of positive charges.
Still, he was proven wrong by his own student, Ernest Rutherford in 1911. According to his experiments, his team shot a positively charged beam at a gold foil, if Thomson’s model was correct, the ball of positive charges won’t be able to repel the beam (Like charge repel each other). Some were deflected strongly, so Rutherford thought that all the positively charges are packed in the middle of an atom. Two years later, a Danish scientist Niel Bohr proposed that electrons orbit in certain orbits. It seemed pretty advanced at that time, but it was soon proven incorrect. In the late 1920s, the cloud model was created. It stated that electrons don’t move in orbits, instead their motion were affected by energy levels. Soon, scientist found particles inside atoms that did not have any charges, called neutrons. Since neutron was neutral, it was really hard to detect. This model was named as modern