 We saw the drawbacks of the Rutherford model. Right? If an electron is orbiting around a nucleus, it means it's accelerating. And if a charge accelerates, it must radiate energy. That means it must fall into the nucleus, making the nucleus highly unstable. So the atom should not even exist. Now that was a drawback of the Rutherford model. It could not explain that. And Niels Bohr, a scientist for the name of Niels Bohr, he came up with a new model of an atom, which was in response to the Rutherford model. And his model had two main points. It said only certain special orbits known as discrete orbits of electrons are allowed inside the atom. Now these special orbits, these are really called energy levels. And the second point said while revolving in discrete orbits or let's say these energy levels, the electrons do not radiate energy. So now according to the Bohr's model of an atom, let's see how an atom would look like. So here we have the nucleus, and you have these energy levels or discrete orbits of electrons around the nucleus. Each orbit has a specific energy. It has a specific energy of its own. And if electrons, if electrons are moving around in this in this energy level, then those electrons have a fixed energy. So these two electrons will have a particular specific fixed energy. Similarly, these electrons that are revolving in this energy level will have a fixed energy. Electrons cannot exist in between energy levels or special orbits. And these energy levels, they have a name of their own. So the first one, the first one is called the K-shell, the one closest to the nucleus. The one next to it is called the L-shell, then you have the M-shell and N-shell and so on. If there are more orbits, then it would go even further. We can even assign numbers to them. So the first orbit is N equals to 1. This is N equals to 2, 3, 4 and so on. Now there are some rules which electrons follow when they are filling these orbits and we will learn about them in some other videos.