First week in chemistry

This week I learned the basics of chemistry. Chemistry is basically the composition of matter and what happens when it experiences change.  The elements are the most basic types of properties. The first forms of matter we learned about were silicon and gold. These are what you call pure substances. They have both unique chemical and physical properties and atoms. What makes these elements so unique is the amount of protons there are in them. There are one hundred eighteen elements. Ninety eight of them are natural and twenty eight of them are artificial. Molecules are two or more atoms that are chemically bonded together. Carbon 12 is the atomic mass standard; it contains six protons and six neutrons. Carbon 12 contains 12 atomic mass units.