CHEM 1A Lecture Notes - Lecture 1: Noble Gas, Hexa, Alkaline Earth Metal

• School: UCSB
• Department: Chemistry and Biochemistry
• Course: CHEM 1A
• Professor: Price

Document Summary

Element: substance consisting of one type of atom. Compound: substance consisting of two or more types of atoms. Most elements are monatomic: i. e. na (s), ar (g), he (g), hg (l) N2 (g), h2 (g), f2 (g), o2 (g), i2 (s), cl2 (g), br2 (l: makes a seven shape on the periodic table. Dalton"s atomic theory: each element is composed of particles called atoms, atoms of the same element are identical, atoms of different elements are fundamentally different, atoms combine in simple, whole-number ratios to form compounds. I. e. nacl, h2o, co, co2, etc: in a chemical reaction, atoms are reorganized to form new compounds. Electrons (negatively charged: much lighter than protons and neutrons, orbit around the nucleus. Element symbol: the number of protons determines the identity of the element. X a= mass number (# protons + # neutrons) Reading a periodic table~ horizontal rows= periods vertical columns= group or family.