BONDING
The process by which elements transfer or share electrons to:
1) Follow the OCTET RULE. for larger elements.
2) Have the configuration of He for small atoms.
3) Release energy (exothermic) to become more thermodynamically stable.
4) Transition Metals and large atoms MAY break the octet rule.
TYPES OF BONDING
Bonds are classified according to IONIC
CHARACTER: the difference of
electronegativity values (table S) of the
TWO atoms involved.
IF the ionic character is
between 1.7 and above,
THEN the bond is IONIC
A metal LOSES electrons and a
nonmetal GAINS them in an
ELECTRON TRANSFER. There
are no molecules formed, exists as
ions or crystal lattice.
The positive and
negative ions
produced form a
crystal lattice
lattice.nomolecules
IF the ionic character is
between 0.4 and 1.7, THEN
the bond is polar covalent
1)
2)
Those ionic
compounds that are
soluble ( table F)
are conductors in
the aqueous
phase. All ionic
substances
conduct when
fussed (melted).
See covalent
concept map
See covalent
concept map
3)
All electrons
are fixed, in
the solid
state, not a
conductor
THE METALS
Group one metals release only one electron and lose the
valence shell to become 1+ ions, the only charge they can
have. Group one metals make only ionic bonds and the
positive ions are SMALLER than the neutral atom.
Group two metals lose two electrons to form 2+ ions, but
may form covalent compounds.
The energy required to remove electrons from an atom is
called IONIZATION ENERGY (table S).
THE NONMETALS
1)
2)
The lattice is hard and brittle
due to the very strong
electrostatic attractions
IF the ionic character is
between 0 and 0.4, THEN the
bond is nonpolar covalent
Non-metals gain electrons to complete the
valence shell octet.
The negative ion is LARGER than the
neutral atom.