Atoms and Bonding
CHEMICAL BONDS
A chemical bond is the force of attraction holding atoms together due to the transfer or
sharing of valence electrons between them.
Atoms react in a way that will make them more stable.
Atoms will either gain, lose or share electrons in order to chemically combine with other
atoms and fill their valence shells.
Ions
-Ions are atoms with an electrical charge due to the loss or gain of electrons.
-Anions have a negative charge due to the gain of electrons.
-Cations have a positive charge due to the loss of electrons.
Forming Ions
During chemical changes aluminum loses its 3 valence electrons, resulting in Al+3.
During chemical changes oxygen gains 2 electrons, resulting in O-2.
How to determine the type of ion:
Metals will lose their valence
electrons to non-metal atoms.
The charge of the ion
corresponds to the # of
electrons lost.
The charge is always (+)
They are called cations.
Non-metals will gain
valence electrons from
metal atoms.
The charge of the ion
corresponds to the # of
electrons gained.
The charge is always (-)
They are called anions.
Types of Chemical Bonds:
Ionic
Covalent (molecular) *
Coordinate Covalent
Network covalent
Metallic
* Covalent bonds (molecular) can be divided into two categories; polar and non-polar.
Ionic Bonds
A metal atom bonds with a non-metal atom.
The valence electrons are transferred. The metal atom loses them and the non-metal atom gains
them.
Ionic bonds form from electrical attraction between anions and cations
Polyatomic ions are made of several atoms and have an overall positive or negative charge
Ionic Compounds
-consist of a combination of cations and anions in which the bonding balances out the negative
and positive charges
- ionic compounds are crystalline, have high melting points, conduct electricity when melted, and
are water soluble.
-in naming ionic compounds, the name of the cation is first followed by the name of the