Download Chemical Bonding

9 Sci - Chemistry
Where is water?
A chemical bond is an attraction between atoms.
Atoms are held together by the interaction of their
outer shells (valence electrons)
Atoms can join together to form larger substances .
Chemical bonds can be either ‘strong’ or ‘weak’
Strong Bonds
» Metallic Bonding – Metal with metal
» Ionic Bonding – Metal with non-metal
» Covalent Bonding – Non-metal with non-metal
Weak Bonds
» Dipole-dipole
» Hydrogen bonding
» Dispersion forces
An ionic bond results from the complete transfer of
one or more electrons from a metal to a nonmetal.
Atoms of different elements can join together to form
new substances.
A substance which is made up of two or more different
types of atoms is known as a compound.
One way this can occur is for atoms to form ions.
What is it?
NON-METAL
METAL
Metals usually want to give electrons (electron doners)
» Becomes positively charged ion (cation)
Non-Metals usually want to take electrons (electron
receivers)
» Becomes negatively charged ion (anion)
» Changes name suffix to –ide (e.g.ChlorineChloride)
The metal will donate the electron to the non-metal
The cation and anion are opposite in charge and become
attracted to each other (electrostatic forces)
Example: Sodium Chloride - NaCl
Example 2: Calcium Chloride
+
=
X2
Calcium Atom
Atomic Number = 20
Valence Electron = 2
Calcium gives 2
electrons to become
stable
Chlorine Atom
Atomic Number = 17
Valence Electron = 1
Chlorine receives 1
electron to become
stable
Calcium Cation = Ca2+
Chloride Anion = Cl-
Calcium joins with 2 Chloride
ions to become:
Calcium Chloride = CaCl2
Table showing Valency of Ions