Bonding models
In a nutshell
Matter is made of atoms that are held together through a variety of forces called bonds and intermolecular forces.
There are 3 types of bonds:
Intermolecular forces are weak bonds that exists between molecules and/or atoms. These forces are weaker than any of the three bonds described above and account for a wide range of physical and chemical properties of elements and compounds, from their melting point and ebullition point to the double helix structure of DNA.
Matter is made of atoms that are held together through a variety of forces called bonds and intermolecular forces.
There are 3 types of bonds:
- Metallic: when positive metal ions are surrounded by a 'sea' of free electrons. Explain the bonding between metal atoms (of the same or different metals) and most physical and chemical properties of metal such as electrical and thermal conductivity, malleability, ductility, melting point and reactivity with nonmetals.
- Ionic: When a metal element reacts with a non-metal element, ions of opposite charge are produced and develop a force of electrostatic attraction between the oppositely charged ions, similar to the attraction between the two opposite poles of magnets. This interaction is called ionic bonding. All salts and most minerals involve ionic bonding.
- Covalent: when 2 non-metal atoms (from the same element or from different elements) share electrons. Covalent bonding explain the formation of molecules, from the simplest H2 molecules (hydrogen gas) to the most complex proteins made of several hundreds of thousands of atoms covalently bonded.
Intermolecular forces are weak bonds that exists between molecules and/or atoms. These forces are weaker than any of the three bonds described above and account for a wide range of physical and chemical properties of elements and compounds, from their melting point and ebullition point to the double helix structure of DNA.
Atoms that bonds and atoms that do not bond
Most atoms join with other atoms to form small groupings called molecules or large, regular arrangements called lattices. The links between these atoms are called chemical bonds.
However, one group of atoms tends not to bond. These are the atoms of elements in group 18, commonly called the noble or inert gases. The atoms of noble gases are extremely stable and rarely bond with other atoms. Instead, they exist as single atoms. This stability is because of their electron configuration. Helium (He) atoms have two electrons filling their outer shells, while neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn) atoms have eight electrons filling their outer-shells.
All other atoms in the periodic table react, gaining, losing or sharing electrons as they do so. This results in particles with full outer shells or outer shells that hold eight electrons. This gives the particles the same electron configuration and stability as a noble gas. This transfer or sharing of electrons is how bonds form.
However, one group of atoms tends not to bond. These are the atoms of elements in group 18, commonly called the noble or inert gases. The atoms of noble gases are extremely stable and rarely bond with other atoms. Instead, they exist as single atoms. This stability is because of their electron configuration. Helium (He) atoms have two electrons filling their outer shells, while neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn) atoms have eight electrons filling their outer-shells.
All other atoms in the periodic table react, gaining, losing or sharing electrons as they do so. This results in particles with full outer shells or outer shells that hold eight electrons. This gives the particles the same electron configuration and stability as a noble gas. This transfer or sharing of electrons is how bonds form.
Select any of the following bond category to obtain more information.