CHEM 51A Chapter 1: Chapter 1

• School: UC-Irvine
• Department: Chemistry
• Course: CHEM 51A
• Professor: Christopher Vanderwal

Document Summary

There are two main components of an atom. Nucleus - most of the mass of the atom; contains protons & neutrons. Electron cloud - most of the volume of the atom ; composed of electrons. Charge of proton equal in magnitude but opposite in sign to charge on electron. In neutral atom, # of protons = # of electrons. Aka atomic number, which is unique to particular element. There are also charged ions - cations & anions. Cations - positively charged & has fewer electrons than neutral form. Anions - negatively charged & has more electrons than neutral form. Number of neutrons in a particular element can vary. Isotopes are two atoms of the same element having different number of neutrons. Mass number is the total number of protons and neutrons in nucleus. Most common isotope of hydrogen has 1 proton & no neutrons; called deuterium, often symbolized by letter d.