Metallic Bonding A metallic bond is the attraction of a ________ _______for ____________electrons Metallic cation delocalized

Electron Sea Model proposes that the nuclei of the metallic cations hold onto their correct ________ of _________, but they may be any valence e- of a neighboring nucleus. They are NOT ______ or _____; they are floating in a sea above the _______ and can move freely from one atom to the next.

Electron Sea Model proposes that the nuclei of the metallic cations hold onto their correct number of electrons, but they may be any valence e- of a neighboring nucleus. They are NOT _______ or _____; they are floating in a sea above the ______and can move freely from one atom to the next.

Electron Sea Model proposes that the nuclei of the metallic cations hold onto their correct number of electrons, but they may be any valence e- of a neighboring nucleus. They are NOT shared or lost; they are floating in a sea above the nuclei and can move freely from one atom to the next.

delocalized electron = Attractions between positive cations and the negative “sea of e-“ hold the metal atoms together in a lattice. The valence e- of a metal that is free to move easily from one cation to another

Properties of metals med. high melting points high boiling points malleable and ductile heat conductors electrical conductors

Brittleness is typical of ionic substances Brittleness is typical of ionic substances. Imagine what happens to the crystal if a stress is applied which shifts the ion layers slightly. Ions of the same charge are brought side-by-side and so the crystal repels itself to pieces!

Malleability of metals Whereas ionic cmpds shatter when hit with a mallet (hammer), metallic cmpds can be flattened and shaped. Why?

As the number of increases, increase. In the transition metals, mobile electrons consist of both the electrons (highest s) and the inner electrons. delocalized electrons hardness & strength valence d

Alloy = mixture of metals; not a cmpd 18 carat Gold Au 75% Ag/Cu 25% Sterling silver Ag 92.5% Cu 7.5% Coinage silver Ag 90% Cu 10% Plumber’s solder Pb 67% Sn 33% Pewter Sn 85% Cu 7.3% Bi 6% Sb 1.7% Brass Cu 60% Zn 39% Sn 1% Steel Fe 99% C 1% Cast Iron Fe 96% C 4% Stainless Steel Fe 80.6% Cr 18% C 0.4% Ni 1%

Types of alloys When two metals with similar size ions are mixed, a alloy is formed examples: substitutional Brass, pewter, 10 carat gold

When one of the metals’ ions is considerably smaller than the other metal, the smaller ions fill in the small spaces (___________) between the larger ones. This is an __________ _____ example: interstices Interstitial alloy Carbon steel

Summary “Sea of electrons” are reason for a metal’s properties Alloys are mixtures of metals Substitutional alloys have similar sized elements Interstitial alloys have different sized elements Metals are malleable (can be flattened) and ductile (can be drawn into wires), and have luster (are shiny)