a substance formed when two or more elements combine chemically in fixed ratios.
The compound has different properties than the elements that combine to form it
Chemical Bonding
the combining of atoms of elements to form new substances
occurs according to certain rules determined by the structure of the atom
The electron arrangement of the outer energy level
of an atom determines whether or not it will form bonds
When the outer energy level is full (usually 8 electrons in outer energy level)
the atom is inert (stable or unreactive) ( I like to think of it as "happy :)" )
To obtain stability ("get happy :)"), elements will do one of the following
gain electrons
lose electrons
share electrons
Types of bonds
Ionic Bonds
formed by transfer of electrons
one atom loses electrons, another atom gains electrons
charged particles Ions are formed
the atom losing electrons is now a positive ion
the atom gaining electrons is now a negative ion
the oppositely charged particles are then attracted to each other
this attraction gives them great stability
because of this, ionic compounds have high melting points
occurs when a metal and a nonmetal react to from a compound
Covalent Bonds
bonding in which electrons are shared
by sharing electrons each atom fills up its outer energy level
both nuclei are attracted to the electrons that are being shared
covalent bonding results in the formation of a molecule
most covalent compounds have low melting points
covalent bonding generally occurs between two nonmetals
Metallic Bonds
Bonding that occurs between atoms of metals
the positive nuclei of atoms are surrounded by mobile electrons
that are all attracted by the nuclei at the same time
the electron sea accounts for the properties of metals:
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