BeginnerTopic 2 of 100Materials & Chemical
Atomic structure and bonding
Ionic, covalent and metallic bonds determine material behaviour.
In depth
Atoms consist of nucleus and electron shells; valence electrons form bonds: ionic (electron transfer, e.g. NaCl), covalent (sharing, e.g. diamond), metallic (electron sea) and weaker secondary bonds. Bond strength and type determine melting point, stiffness, conductivity and ductility.
Key points
- Bond energy curve
- Stiffness relates to curvature of the potential well
- Electronegativity
ExampleDiamond is extremely hard because of a 3D network of strong covalent bonds.
Bonding type controls melting point, stiffness, conductivity and brittleness, so it explains most of the behaviour of a material.
What is Atomic structure and bonding?
Ionic, covalent and metallic bonds determine material behaviour.
Why is it important to understand atomic structure and bonding?
Bonding type controls melting point, stiffness, conductivity and brittleness, so it explains most of the behaviour of a material.
What is metallic bonding?
Electrons are shared across a lattice of positive ions, which allows electrical and thermal conduction and gives ductility.
Why are covalent solids hard?
Strong directional bonds resist deformation, so covalent solids like diamond and silicon carbide are very hard and stiff.
How is Atomic structure and bonding used in practice?
Typical applications include explaining why ceramic salts are brittle while metals bend, predicting why diamond is hard and an electrical insulator and selecting a conductor using metallic bonding.
What should I learn before Atomic structure and bonding?
Study "Classes of engineering materials" first (topic 1 of 100 in Materials & Chemical). It covers the groundwork this topic builds on.
What are the key points of Atomic structure and bonding?
Bond energy curve. Stiffness relates to curvature of the potential well. Electronegativity.
Can you give an example of Atomic structure and bonding?
Diamond is extremely hard because of a 3D network of strong covalent bonds.
What comes after Atomic structure and bonding?
The next topic is "Crystal structures", which builds directly on this one.
How difficult is Atomic structure and bonding?
It is classed as Beginner in Materials & Chemical (topic 2 of 100). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.