Draw an MO energy-level diagram for beryllium metal, and...

Name: Problem 62, Chapter 21: Chemistry
Uploaded: 2020-08-12T20:58:04-08:00
Duration: 1 min 35 s
Channel: Jorge Villanueva
Description: Draw an MO energy-level diagram for beryllium metal, and show the population of the MOs for the following two cases: (a) The and bands are well separated in energy. (b) The and bands overlap in energy. Which diagram agrees with the fact that beryllium has a high electrical conductivity? Explain.

Draw an MO energy-level diagram for beryllium metal, and show the population of the MOs for the following two cases: (a) The and bands are well separated in energy. (b) The and bands overlap in energy. Which diagram agrees with the fact that beryllium has a high electrical conductivity? Explain.

Draw an MO energy-level diagram for beryllium metal, and show the population of the MOs for the following two cases:
(a) The and bands are well separated in energy.
(b) The and bands overlap in energy. Which diagram agrees with the fact that beryllium has a high electrical conductivity? Explain.

Key Concepts

Fermi Level and Electron Occupancy

The Fermi level represents the highest occupied energy level at absolute zero temperature. Its position relative to the energy bands determines electrical properties. A partially filled band at the Fermi level, especially due to band overlap, means there are available states for electrons to move into, which is essential for high conductivity.

Band Overlap and Electrical Conductivity

In metals, electrical conductivity is high because the conduction band overlaps with the valence band or is only partially filled. Band overlap or a partially filled band allows electrons to move freely under an applied electric field without needing to overcome a significant energy gap, thereby facilitating conduction.

Energy Band Formation

In solids, the discrete energy levels of individual atoms merge into energy bands due to the overlap of atomic orbitals in a periodic lattice. This formation of bands explains how electrons can occupy a wide range of energies and why there are bands separated by energy gaps in insulators and semiconductors or overlapping bands in metals.

Molecular Orbital Theory for Solids

This concept involves the extension of molecular orbital theory to solids, where atomic orbitals from many atoms combine to form molecular orbitals that spread out into continuous energy bands. It helps in understanding how bonding and antibonding interactions occur over a lattice and set the stage for explaining electronic properties in metals.

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