Metallic Properties Main Concept: The interaction of electromagnetic waves or light with matter is a powerful means to probe the structure of atoms and molecules, and to measure their concentration.  

Metallic Properties Metallic Bonding – How Atoms are Arranged Properties of Metals Conductivity Malleability/Ductility Kinds of Alloys: Properties: Interstitial Substitutional

- metallic solids can be represented as positive kernels (or cores) consisting of nuclei and inner electrons of each atom surrounded by sea of mobile valence electrons

Metals are: - good conductors b/c the electrons are delocalized and relatively free to move. - malleable and ductile b/c deforming solids does not change environment immediately surrounding each metal core

- Metallic solids are often pure substances, but may also be mixtures called alloys. - size of the component atoms can help us understand some properties of alloys (interstitial and substitutional):

Interstitial Alloys: - form b/w atoms of different radius, where smaller atoms fill interstitial spaces between the larger atoms Example: Steel – carbon occupies the interstices in iron - atoms make lattice more rigid, decreasing malleability and ductility

Substitutional Alloys: - form b/w atoms of comparable radius, where one atom substitutes for the other in the lattice Example: Brass – some of the copper atoms are substituted with a different element, usually zinc - density typically lies between component metals - like interstitial alloys, substitutional alloys are less malleable and ductile than pure metals

- Alloys typically retain a sea of mobile electrons and so remain conducting - surfaces of a metals or alloys are often changed through a chemical reaction Example: formation of a chemically inert oxide layer in stainless steel, through reaction with oxygen in the air.

Effects of oxidation: