Chapter 5 Electrons In Atoms
Section 1
Key concepts
Rutherford’s atomic model could not explain the chemical properties of elements.
Bohr proposed that an electron is found only in specific circular paths, or orbit, around the nucleus.
The quantum mechanical model determines the allowed energies an electron can have and how likely it is to find the electron in various locations around the nucleus.
Each energy sublevel corresponds to an orbital of a different shape, which describes where the electron is likely to be found.
Vocabulary
Energy levels – The fixed energies an electron can have are called energy levels.
Quantum – A quantum of energy is the amount of energy required to move an electron from one energy level to another energy level.
Quantum mechanical model – The modern description of the electrons in atoms, the quantum mechanical model, comes from the mathematical solutions to the Schrodinger equation.
Atomic orbital – An atomic orbital is often thought of as a region of space in which there is a high probability of finding an electron.
The Development of Atomic Models
The model for the atom consisted of protons and neutrons making up a nucleus surrounded by electrons. Rutherford used existing ideas about the atom and proposed an atomic model in which the electrons move around the nucleus, like the planets move around the sun.
The Bohr Model
Niels Bohr (1885-1962), a young Danish physicist and a student of Rutherford’s model needed improvement. In 1913 Bohr changed Rutherford’s model to include newer discoveries about how the energy of an atom changes when it absorbs or emits light.
The Quantum Mechanical Model
The Rutherford planetary model and the Bohr model of the atom are based on describing paths of moving electrons as you would describe the path of a large moving object.
How likely it is to find the electron in a particular location is described by probability.
The quantum mechanical model description of how the...