Chemistry 112

1. Chemistry 112 Models of the Atom

2. Development of Atomic Models • A shortcoming of the discovery of the nucleus and advancements in an atomic model was that it failed to explain chemical behavior • A model that focused on the electron was needed • Bohr built on Rutherford’s model to include the energy within an atom • He suggested that electrons existed within circular paths, called orbitals, outside the nucleus • Every electron within an orbital possesses a certain amount of energy • They were then called energy levels

3. The Energy of Electrons • The e- with the lowest energy are found in the first energy level • e- can move from one orbital to another but only if it gains or loses energy • The further an e- is away from the nucleus, the more energy it possesses • The amount of energy an e- must absorb/release to move from one orbital to another is called a quantum • The amount of energy to move from one orbital to the next is not always the same

4. Bohr’s Model • The model of the atom was better understood but still failed to explain all the properties of atoms with atomic numbers greater than hydrogen • Information was being gathered by other scientists on waves and energy that did not correspond with Bohr’s model

5. Quantum Mechanical Model • Schrodinger used information about electron motion to devise and solve a mathematical equation that described the behavior of the electron • The amount of energy an e- possesses is still considered fixed but the pathway is not • QMM takes into consideration the amount of energy an e- has and how likely it is to be found in a certain location (probability) • e- are most likely to be found close to the nucleus