CAS CH 102 Lecture Notes - Lecture 16: Atomic Number, Chemical Formula, Boron

• School: Boston University
• Department: Chemistry
• Course: CAS CH 102
• Professor: Lee

Document Summary

We can find average atomic mass of an element, atomic weight, by using masses of isotopes and their relative substances. Most accurate means for determining atomic weights. It gives a chemical fingerprint of the molecules and gives clue about how the atoms were connected in the original molecule: the periodic table. If the elements are arranged in order of increasing atomic number, their chemical and physical properties show a repeating or periodic pattern. The arrangements of elements in order of increasing atomic number, with elements having similar properties placed in vertical columns is known as the periodic table. Periods- horizontal rows of the periodic table. Elements in a group often show similarities in physical and chemical properties. They have the same properties because they have the same arrangement of electrons at the edge of their atoms. All the metallic elements share characteristic properties such as luster, high electrical and heat conductivity, except mercury (hg) are solid at room temperature.