SPM Form 4: Chemical Bonds (Checklist)
- An ionic
bond is a chemical link between two atoms caused by the electrostatic
force
between oppositely-charged ions in
an ionic compound. Examples: an ionic bond between the sodium and chloride ions
in table salt, NaCl.
- A covalent
bond is a chemical link between two atoms in
which electrons are
shared between them. Examples: a covalent bond between the oxygen and hydrogen
in a water molecule (H2O).
- Ionic compounds: a compound
that consists of positive ions and negative ions arranged in the crystal
lattice and are attracted to each other by strong electrostatic forces. Ionic
compounds such as magnesium oxide, MgO, sodium chloride, NaCl and iron(III)
chloride, FeCl3 can be respectively prepared through a reaction
between a metal and a non-metal.
- Covalent compounds are those
in which the elements share electrons via covalent bonds.
- Ionic compounds have high
melting and boiling point whereas covalent compounds have low melting and
boiling points.
- Ionic compounds are mostly
soluble in water but insoluble in organic solvents. Covalent compounds are
mostly insoluble in water but soluble in organic solvents.
- Ionic compounds can conduct
electricity in molten state but cannot conduct electricity in solid state.
Covalent compounds cannot conduct electricity in solid and molten states.
- Melting points: the
temperature at which a solid turns into a liquid at a fixed pressure.
- Boiling
point: the temperature at which the vapor pressure of
a liquid equals
the external pressure surrounding
the liquid.
- Solubility: the maximum
quantity of a substance that may be dissolved in another or the maximum amount
of solute that may be dissolved in a solvent.
