 Today, we're going to talk about atoms and atomic structure. Atoms are the smallest unit of an element that retain the properties of that element. So if you have an element like copper and you cut it up into the smallest possible pieces that you can possibly cut up, you still would not be to that level of an atom. An atom cannot be seen with the naked eye. You would need a special microscope to see an atom. So they're very, very, very tiny. The atoms can be combined to form compounds. So we can combine atoms of copper with atoms of oxygen to make the compound copper oxide. The atoms themselves are made up of three different types of subatomic particles. Those subatomic particles are called protons, neutrons, and electrons. And they are combined to form the atom. The proton has a charge of positive 1. Its mass is approximately one atomic mass unit, AMU. And atomic mass unit is on the magnitude of 1 times 10 to the minus 24th grams. So tiny, tiny, tiny. It's very small and you can't see it with the naked eye. The protons are located in the nucleus of the atom. Neutrons have a charge of zero. They are neutral. Their mass is approximately one AMU as well. So protons and neutrons are about the same size. And it is also located in the nucleus of the atom. Electrons are negatively charged. They have a negative one charge. Their mass is so small that it's basically negligible. So we can assume it's zero for our purposes in this course. Its location is not in the nucleus along with the protons and the neutrons. It is actually outside the nucleus. And based on this sketch of an atom, the nucleus is the dense core in the center of the atom that contains the protons and the neutrons. The area outside the nucleus is called the electron cloud. The reason it's called a cloud is because there's really not a definitive edge around it. The electrons are moving around the nucleus in this general area. So the positively charged protons and neutral neutrons are in the center in the nucleus. The negatively charged electrons are outside the nucleus in the electron cloud. The basic structure of an atom is the same for all elements. What is going to differ is the number of subatomic particles in each of those different types of elements. And using this information, we will progress into learning about the different types of atoms and how to differentiate between atoms of different elements.