Atomic structure, proton, electron and neutron. Before starting the lecture, click on the subscribe button and get access to our hundred of conceptual lectures for free. Well, we know that everything is made up of atoms. For example, consider salt, sugar and water, they all are made up of atoms. Even plants. Animals and human beings are also made up of atoms. Now the important question is what makes up atoms? Well, there are three tiny particles that make up atoms. Proton, electron and neutron. Remember that the ship of any atom is spherical like a ball. The structure of all atoms is the same. There is a dense central part in any atom known as a nucleus. Secondly, there are fixed parts around the nucleus known as energy levels or shells. The protons and neutrons live in the nucleus, while electrons are revolving around the nucleus just like planets revolve around the sun. Here is one of the important questions that why electrons revolve around the nucleus? Or what causes electron to revolve around the nucleus? Well, remember that proton is a positively charged particle and electron is a negatively charged particle. There is electrostatic force between them. As a result of this force, electrons constantly revolve around the nucleus. Now what about neutrons? Well, neutron is a neutral particle. It means it doesn't carry either positive or negative charge. Now let me teach you, an atom as a whole is a neutral particle. For example, consider a hydrogen atom. We know that there is only one proton in the nucleus of hydrogen and only one electron that is revolving around the nucleus. So we can write proton is equal to positive one because protons are positively charged particles. And we can write electron is equal to negative one. Because electrons are negatively charged particles, we know that positive one and negative one cancel out each other. Thus this single positive proton neutralize this single negative electron. From this example, we learn that number of protons is equal to number of electrons in any atom. Let me repeat it. Number of protons is equal to number of electrons in any atom. Thus we therefore say that an atom as a whole is a neutral particle. Now let me teach you something amazing that happens when the number of protons and electrons increase inside the atom. Let consider the helium atom. We know that there are two protons in the nucleus of helium and two electrons that are revolving in the first shell. Now let me ask you, these two protons have same charge, I mean positive charge. Are they repelling each other? Well, the answer is absolute yes. According to physics conventions, like charges repel each other. If they repel each other then the structure of nucleus will get disturbance which is not acceptable. Can you guess something? Well, here comes the part of neutrons. As I told you that neutrons are electrically neutral particle. Two neutrons in the helium nucleus come in action and separate this positive proton from this positive proton. You can also learn the function of neutrons in the nucleus as consider two current carrying wires touching each other but they are protected by the plastic insulation. Similarly, these neutrons act as a plastic insulation between or among positively charged protons. So, by this way repulsion among positively charged protons are minimized inside any atom. Secondly, consider an atom of lithium. There are three protons in the nucleus of lithium atom and there are three electrons revolving around the nucleus. Just like protons, electrons also repel one another. But there is not only one shell or energy level and the lithium atom. There are two shells or two energy levels and the lithium atom. First shell can hold only two electrons. Thus this electron will jump into the second shell. Second shell, our second energy level is bigger than the first shell and can accommodate up to 8 electrons. Also we know that there are different energy levels like K, L, M and N. So by this way repulsion among negative charges are minimized. To summarize my lecture. We learn that an atom is made up of three tiny particles, proton, electron and neutron. Secondly, we learn that an atom as a whole is electrically neutral because the number of protons is equal to number of electrons. Thirdly, we learn that neutron minimize the internal repulsion among protons and the nucleus. Finally, we learn that an atom consists of many shells to reduce the internal repulsion among electrons. This was all about atomic structure, proton, electron and neutron.