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Beaker Breaker Draw the Lewis structure of the following polyatomic ions:. nitrite ion sulfite ion. Metallic Bonding. 6-4. Do metals have “few” or “many” valence electrons?. How do they achieve “stability” ?. Metallic Bond Model. metals have very few electrons in their highest E level
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Beaker BreakerDraw the Lewis structure of the following polyatomic ions: • nitrite ion • sulfite ion
Metallic Bonding 6-4
Do metals have “few” or “many” valence electrons? • How do they achieve “stability” ?
Metallic Bond Model • metals have very few electrons in their highest E level • metals frequently have many vacant d-orbitals just below the outer level • vacant orbitals of adjacent atoms overlap which allows these loosely held e-s to roam freely
Metallic Bond Model (con’t) • “delocalized electrons” - e-s don’t stay in one locality like… • covalent bonding: stay in the overlapping of the shared orbitals • ionic bonding: e-s are bound to an ion within a crystal lattice • mobile electrons form a “sea of electrons”
Metallic Bonding • the chemical bonding that results from the attraction between metal atoms and the surrounding sea of electrons • mutual sharing of many e-s where each atom contributes its valence e-s which are then free to move about the mostly vacant outer orbitals of all the metal atoms
So…why are metals…. • good electrical conductors? • good thermal conductors? • shiny? • malleable/ductile?
Metallic Properties • High electrical & thermal conductivity • due to high mobility and delocalization of e-s • Luster (shine) • metals absorb E and become “excited” very easily because many of their orbitals are separated by extremely small ∆E…shine occurs when photons are emitted when excited e-s return to ground state
Metallic Prop. (con’t) • Malleability (ability to be hammered/beaten into thin sheets) and ductility (ability to be drawn, pulled, or extruded to produce wire) because metallic bonding is the same in all directions and a shift in layers of atoms is inconsequential
Metallic Bond Strength • Expressed in the heat of vaporizationvalue where the bonded atoms in the metallic solid state are converted into indiv. metal atoms in the gaseous state (usually↑heat of vap, the ↑ the bond strength) • Determined by • strength of nuclear charge & # delocal. e-s
What is the difference between…- Bond energy ??- Lattice energy ??- Heat of vaporization ?? Hint: • What kind of bonding is generally involved when this term is used? • Is energy being added or taken away?
What is the difference between…- Bond energy ??- Lattice energy ??- Heat of vaporization ?? • Bond energy: E added to break a covalent bond • Lattice energy: E released when ionic cmpds are broken down into atoms • Heat of vaporization: E added when bonded, metallic, solid atoms are broken into indiv gaseous atoms