Eng 45 - Chapter 1 - Structure(20)

Eng 45 - Chapter 1 - Structure(20) - Materials Scien ce...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Materials Science Fall, 2007 Page 19 interact. For simplicity we consider a single atom pair, though the same considerations apply to groups of atoms in molecules and solids. 2.3.3 Shared valence electrons: covalent and metallic bonding In the first mechanism the valence electron clouds interpenetrate so that, effectively, the atoms share electrons. This is the most potent mechanism of bonding. When an electron in an orbital about one nucleus penetrates the electron cloud of the other it feels the electrostatic attraction of both nuclei, and its energy is lowered substantially. However, the Pauli exclusion principle severely restricts the extent to which the electron clouds can penetrate one another. When an electron on one atom penetrates the electron cloud of another its charge density overlaps into the occupied orbitals of that atom. This is forbidden unless the orbitals are only partly filled; atoms can only share electrons if there are empty states in the outer, valence shells of each. The
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

Eng 45 - Chapter 1 - Structure(20) - Materials Scien ce...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online