Concept of Weekend Reading

Weekend Reading

By Kelly Moran 

For this weekend's reading, we had to read some sections of Chapter B. In this reading, I learned mostly about the periodic table and how the elements in it work. First of all it was created by Dimitri Mendeleev, a Russian chemist, who published it in 1869. The periodic table has a pattern that resembles a monthly calendar. Early Periodic tables were organized by two characteristics which were physical and chemical. Chemists in the early ages knew that elements had different masses. From comparing elements, an average atomic mass was created for each element in Mendeleev's periodic table. I also learned that in the periodic table the elements contain electrically neutral atoms. There are electrons in atoms (which are negatively charged particles) and protons (positive charge). An electrically neutral type of atom contains the same amount of protons to electrons. Neutrons are one or more electrically neutral particles. The atomic number of an element is the number of protons. The nucleus is a concentrated region of positive charge because of protons. The mass number is equal to the sum of protons and neutrons. Atoms with the same number of protons but a different number of neutrons is called an isotope. The number of neutrons in an element can be found by subtracting the number of protons from the mass number. These are all the key themes and facts that I learned in the weekend reading!