Individual Atoms not having Same Properties as Bulk Materials

Properties of Metals

Metals have a crystalline structure which is arranged in regular layers.
In metals, the valence electrons are not associated with a single atom but are delocalised, moving freely throughout the metal lattice, forming a ‘sea’ of electrons.
This gives metals properties such as good electrical and thermal conductivity, since the electrons can carry charge and heat through the lattice.
Metals are malleable and ductile due to the ability of the layers of atoms to slide over each other without breaking the metallic bonds.

Ionic compounds are formed when atoms transfer electrons to form ions. When a metal and a non-metal react, the metal atom loses electrons and the non-metal atom gains electrons.
These compounds form regular lattice structures due to the ionic bonds between the positive and negative ions which are strong and operate in all directions.
Ionic compounds have high melting and boiling points because of the large amounts of energy required to break the many strong ionic bonds.
When in solution or in a molten state, ionic compounds can conduct electricity as the ions are free to move and carry charge.

In covalent substances, atoms share electrons to achieve a full outer shell.
Covalent bonds are found in small molecules, larger structures like diamond (a form of carbon) and polymers, and in giant structures like quartz (silicon dioxide).
Simple covalent molecules do not carry a charge and have low melting and boiling points. They are generally gases, liquids or low melting point solids.
Substances with a giant covalent structure have high melting and boiling points because of the large amounts of energy required to break the many strong covalent bonds.
Unlike ionic compounds, covalent substances generally do not conduct electricity because they do not contain charged particles that are free to move.