Metallic Bonding Flashcards
Achieving Stability
Metal Atoms achieve stability by “off-loading” electrons to attain the electronic structure of the nearest noble gas. These electrons are delocalized and form a “mobile sea of electrons” which prevents newly formed positive ions from flying apart due to repulsion of similar forces.
Conductor - Metals
Metals are good conductors because the sea of electrons are mobile.
The valence electrons are free to move through out the structure.
Electrons attracted to the positive end are replaced by the electrons entering the negative end.
Mobile electron cloud allows for conductivity.
Change in Shape - Metal
They can change there shape easily.
Malleable - can be hammered into sheets
Ductile - can be drawn into rods and wires.
Bonding between metal ions and the delocalized electrons is non-directional. Individual metal atoms can move in relation to each other without breaking bonds between them and the sea of electrons.
Solid at Room temperature - metals
strong attractive forces of between the metal ions and sea of electrons hold the metallic lattice together. As a result a moderate to high temperature is needed to disrupt the lattice and allow the metal to melt.
Melting points
Melting point is a measure of how easy it is to separate individual particles. In metals it is a measure of how strong the electron clouds hold the + ions.
It increases across the period. The electron cloud density increases as more electrons are donated per atom as a result the ions are held more strongly.
Melting point decreases down a group- Ionic radius increases down a group. As the ions get bigger the electron cloud becomes less effective holding them together so they are easier to separate.
