CHEM 121 Chapter Notes - Chapter 1: Dmitri Mendeleev, Alkali Metal, Arsenic
Document Summary
Element (fundamental substance that can"t be chemically changed or broken down into anything simpler. 83/90 or so naturally occurring elements are found on earth in any appreciable abundance. 10 elements known since beginning of recording history. First new element to be found in several 1,000 years was arsenic (as), in 1251. 24 elements were known when us was founded in 1776. Periods (7 horizontal rows on periodic table) Groups (18 vertical columns on periodic table) Main groups (2 larger groups on left and 6 larger groups on right) Transition metal groups (10 smaller groups in middle of table) Inner transitional metal groups (14 groups shown separately at bottom of table) 1. 3: some common groups of elements and their properties. Property (any characteristic that can be describe or identity matter) Intensive properties (have values that don"t depend on amount of sample) Extensive properties (have values that do depend on sample size)
